You are probably not playing as foccused as you used to be when you were 1500,one method is not to play for 10-15 days and then you might be more foccused.
What is going on with my chess?
You don't have to give up chess but to play good chess you really do need to know basic strategies like how to play passed pawns, value of rooks on the 7th and King placement for endgame, which might've come in handy in the 2nd game posted.
To get there, probably need to get a good middle game book. My favorite is Larry Evans "New Ideas in Chess". It's really easy to read and you don't have to go cover to cover but just poke around really short chapters or go straight to what's interesting. Plus it's cheap.
Then, as most have wisely advised, play some standard to get experience in the strategies and help with calculation and board visualization.
I'm guessing you'll almost certainly become a better player if you study even a little, practice it via standard, and work on calculation.
lol
im a 1900 player who got there OTB solely because of blitz.
learn openings and positions you like to play with blitz.
its very important.

You don't have to give up chess but to play good chess you really do need to know basic strategies like how to play passed pawns, value of rooks on the 7th and King placement for endgame, which might've come in handy in the 2nd game posted.
Do you really think i don't know these basic things? I won a lot endgames.

Speaking about my first loss against Philidor defence engine says that even after a3 i had an edge but a little better was of course to play h4 and just to retreat my knight after ... b4 to e2 square. But a3 wasn't the mistake and i could have initiative. So this variant is ablsolutely fine for white. Mistake was 18. Nd5. Instead i should have played 18. axb. And 18. ..bxa of my opponent was huge blunder. I needed to play 19. Nxf6 with +8 or +9 (I may look scary after 19. Bxf6 but white has huge attack after Rxh7+ and black will give up a bishop and a queen very soon) but instead i made my own blunder 19. bxa with -5.

Damn 19. Nxf6 and then 20. Rxh7 looked real good for game 1.
I saw that potentialy this position is crushing for black, i just needed to find the right move which unfortunately didn't happen. The funny thing is that i saw 19. Nxf6 Bx6 10 Rxh7+ but i rejected it because i didn't see that time how i can prove this sacrifice.

In your Philador game you were doing just fine and probablly winning until you played 11. a3? which transposed a likely win to a likely loss.
You need to learn the basic opening principle not to move a pawn where you have 0-0 or 0-0-0ed in front of your king especially where both sides have castled on opposite sides.
Breaking this basic opening principle changed your game from win to loss.
Hopefully, you will take this advice to heart and learn as it will make a big difference in your future games and ratings and results.

In your Philador game you were doing just fine and probablly winning until you played 11. a3? which transposed a likely win to a likely loss.
You need to learn the basic opening principle not to move a pawn where you have 0-0 or 0-0-0ed in front of your king especially where both sides have castled on opposite sides.
Breaking this basic opening principle changed your game from win to loss.
Hopefully, you will take this advice to heart and learn as it will make a big difference in your future games and ratings and results.
I know such basic rules very well(It's ridiculous to not know them). I made a3 probably because of the losing streak was happening. And engine thinks that it was just inaccuracy in that postion but not the mistake. And i remember my feelings when i saw winning line "19. Nxf6 Bx6 10 Rxh7+" i was sure that i will lose anyway and i didn't look to it deeply.

You played a3 even though you knew it was wrong?
I do not think you realize it was at that point your game turned from winning to losing? there were other winning lines for Black way before the 19th move.

You played a3 even though you knew it was wrong?
I do not think you realize it was at that point your game turned from winning to losing? there were other winning lines for Black way before the 19th move.
Exactly. I understood that it's bad move but i didn't think clealy that time(because of this losing streak) and couldn't find this simple plan with knight retreat. Sometimes players play bad moves because they can't find better. What kind of winning line for black? I could win this game on move 19 not black.

Sorry, I made a mistake. While a3 was a bad move, you had such an overwhelming attack that you still have an advantage after that error.
Black should have tried b5 and c5 but still you have an advantage.
your opening was fine. I have played 6. Bf4 myself and know it is a good move.

Sorry, I made a mistake. While a3 was a bad move, you had such an overwhelming attack that you still have an advantage after that error.
Black should have tried b5 and c5 but still you have an advantage.
your opening was fine. I have played 6. Bf4 myself and know it is a good move.
Yes, Bf4 definately is a good move some people just don't know it.
keep playing your level friends, is the only remedy, as you feel hungry, and the talent, the meaning and the most important, the art or the spirit(aura) will come with time!
All you people touting playing standard games online are different.
Some people dont want to sit infront of a computer screen for a couple hours to play 1 long game. As soon as you get to 1500 or so, it gets really hard to find an opponent.
And i prefer playing longer games OTB because i can review my game with my opponent when i get wrecked.

Btw, I just spent 2 minutes looking at the position in the original game (post #1) after 18. Nd5 ... bxa3 and it looks to me like white is completely won at that point, unless I missed something sinister. Ponz may also be interested.
My first thought was that obviously 19. bxa3 is terrible and white's correct move is b2-b3. But then it struck me that white has 19. Nxf6 and black's intermediary ab+ doesn't achieve anything, since white has Kb1.
So White may be threatening 19 ... Bxf6 20 g5 (to displace or block the f6 bishop) ... (bishop moves) 21. R x h7 ... KxR 22 R h1+ etc.
I need to look at it on a board really. Don't own an engine.
Not 20. g5 but 20. Rxh7! And after 20. ... Kxh7 21. Rh1+ Bh4 22. Bg5! and black is in big trouble. Rxh4+ is comming and black king is in awkward position. I again had very good postion but blew it away with last move.
I doubt any strong chess players will tell you they became strong chess players through playing a lot of blitz . I have played over 100,000 games of blitz online and they havent made me stronger in slow chess and I dont expect them to . I play blitz for fun/relaxation . I play classic otb tournament chess and study to become stronger ...