My Blitz Spike...

So...2 days ago...my blitz was 386....I played in a couple tournaments...and now am at 550+...I can beat higher rated players once in awhile...recently beat a 1000 in blitz....How does this happen?

ratings are inaccurate 

i was 680 and now im 800 in just 40+ games

yup lol

Just one thing to say, whenever I play low rated opponent in bullet, I lose some but win the most of them. But because the stress of losing rating points I just make some horrible blunders sometime. 

In rapid I am just crushing lower rated opponent. Because I don't make blunders.

It seems like you doubt your own abilities quite often.  It really is this simple, if you outplay your opponent you are likely to win.  

The rating is a measure of long term success or failure.  It is in essence meaningless on a per game basis where all it really should be good for is to predict the likely outcome. 

It is not buying into the thought that you cannot beat a higher rated player that is always the tricky part that is much easier said than done (myself included).  And of course at the same time you have to guard against your expectation to beat lower rated players and put forth the necessary effort to win.  Still be confident, just not overconfident.

Ratings around say, 1000 can be a new player whose rating doesn't reflect much except their guess at how good they are at chess upon joining. There's another such zone at 1400 and 1600 where people who can beat Dave and their Uncle Matt choose to begin their spiral down to 241. 

Sometimes you just play better chess ¯\_(ツ)_/¯

Are you joking? Ratings are inaccurate? Lol.

even new players can choose expert assuming they are expert LOL

and expert players can choose new to chess so they can always win

Yes, and ratings stabilise to stop that. Dunning-Kruger. 

You have no idea how rating systems work and yet are criticising them. 

I think a lot of people have jumps in rating when under 1000. There's not too much difference in skill at that level.