Hi !
Since I'm back in lichess, I played some rated games without changing my rating.
Is it normal ?
It certainly is not. Your profile states:
This player artificially increases/decreases their rating
That should be the problem here..
I didn't do anything like that :) . Just stopped playing during some months.
How can I fix this problem ?
Well then I suggest you read this:
en.lichess.org/qa/258/all-about-cheating-questions-and-answersand in case it really does not apply on you contact:
lichess.contact@gmail.com
Good luck!