That's weird. I am an amature in chess, but i like to play blitz in 5 minutes. I used to have 800-900 rate, and i have been staying in this section for an year since I started playing it, and it felt that it is totaly my level. Players with ratings lower than 750 were really easy to beat. But recently something happened and i can't get higher than 700-720. Does somebody know what happened? Maybe an update?
It wasn't due to an update. 150 points isn't that unusual for a drop. Just be patient. It will come back.
To me, it looks like you only really started in February. That's not very long ago.

I also noticed that you resign a lot more often than you get resigned to. Many grandmasters say that you should never resign. I don't agree that you should never resign but perhaps you should fight on more often than you do.
That's weird. I am an amature in chess, but i like to play blitz in 5 minutes. I used to have 800-900 rate, and i have been staying in this section for an year since I started playing it, and it felt that it is totaly my level. Players with ratings lower than 750 were really easy to beat. But recently something happened and i can't get higher than 700-720. Does somebody know what happened? Maybe an update?