Fayez, you must be, Ah, mad as hell.
I lost 10 games in a row
Always check your intended move is no blunder before you play it.
Whenever you lose a game, stop playing and analyse it first so as to learn from your mistakes and avoid mental tilt: channel the negative emotions of the loss towards a positive goal: improving.

Remember this and always keep it in mind:
NO ONE CARES!
No person on Earth visits your profile and has a particular interest in your ratings or your game history! If ratings go up, only you care! If ratings go south, no one is saddened by it. You must become as indifferent and inconsiderate towards this stupid rating number as any of your previous opponents, or else you'll lose focus. The game stops being fun and you become depressed because you lost ... not money, not food, not a loved one,... NO, you drag yourself down because of some meaningless Internet points! How ridiculous would that be, am I right?
Canned Asparagus is getting a bit too deep about it hhaha, I'd suggest a days break from chess and do something to refresh your mind and ease yourself back in with some puzzles. If you're blundering a lot that may be because of tilt, don't play whilst tilted lol speaking from experience.

What should I do? In most of the games, I started with a good position and then blundered to tactics and then lost
Frustrating, but streaks like these happen a lot. You can try implementing a stop-loss system like stock brokers and poker players often employ (if losing 10 in a row is more frustrating than you'd like to handle), but other than this, there isn't a ton you can do to manage variance. Best you can do is maintain your composure to avoid tilt and make sure you are playing with good mindset and good form.
The exact scenario of losing a lot and having a superior position for pretty much the entire game, but then blowing it at one juncture (not always so obvious, but usually tactical) I've suffered many times. Luckily, I've noticed that this tends to happen roughly a month or so before a huge rating boost when you climb even higher than you lost!
Best you can do now if try to laugh it off and come back another day/session to play your best chess
https://www.youtube.com/watch?v=jUpfaoWY1bs
https://www.chess.com/forum/view/fun-with-chess/my-online-chess-rating-59795420

Remember this and always keep it in mind:
NO ONE CARES!
No person on Earth visits your profile and has a particular interest in your ratings or your game history! If ratings go up, only you care! If ratings go south, no one is saddened by it. You must become as indifferent and inconsiderate towards this stupid rating number as any of your previous opponents, or else you'll lose focus. The game stops being fun and you become depressed because you lost ... not money, not food, not a loved one,... NO, you drag yourself down because of some meaningless Internet points! How ridiculous would that be, am I right?
Perhaps you mean well, but this underscores the emotional element of it and completely ignores the psychological element of chess improvement, determination and progress. Maybe not many others care, or obsess over your chess.com profile, but the player cares (and sometimes a lot!) and that is what matters.
True, ratings shouldn't be obsessed over too much, but it isn't the number which is the issue - it is the hard work and struggle; it is the almost helpless feeling and doubt if you are even improving...these are the enemy thoughts which creep into the minds of just about every person here. We are human after all.
I find some refuge in knowing that my chess milestones never change. Say I cross chess.com 1500 rating for the first time, that milestone is forever met and nothing can take that away! Sure I may drop below 1500 temporarily in the future, but the fact I was once there doesn't change. Same is true for every new rating high and milestone.
My advice to the op is to view ratings from this perspective and ideally should result in caring slightly less about the fluctuations in rating on the journey and more celebration on the peaks in rating as they come

Hmm ..., guess we all have our own coping mechanisms after a particularly bad streak.
I view it like this: Every person is a large book, with a wondrous, intricate tale written in it. And I'm merely a footnote.
I used to be sad, angry, downtrodden etc. after a losing streak until I realized that those negative emotions are superfluous. If I stop caring, it's as if it never happened, because as I just described, no one does. Beginning from the start of a new game I'm the same, emotionally and mentally, as before the losing streak took place. Fresh, calm, just content with myself, knowing that I always gave it my best. This mindset doesn't make a better chess player out of you, but a significantly happier, unburdened one.

I lost 7 in a row. I took 2 weeks off. My own experience, I can play too much chess. Like going into highway trance when driving too long, likewise I get into chess trance when I play too much. I just don't see the board as well. My sweet spot seems to be 3 - 5 games per week. You need to find your own sweet spot
What should I do? In most of the games, I started with a good position and then blundered to tactics and then lost