I demoted from S1 to S4 in a week

Hi!! First post here, look for another perspective. I've played the game for s long time now and I decided to rank a little this year, cause I was feeling like it. I began in B4 and climb y like a week to silver 1 with a 70% win rate. Then, I don't know what happened but I started to loose almost every game for like 2 weeks now. I was stomping and I rarely loose lane.

My question is, is this normal? I think I'm improving so much in everything, Laning phase, farming, macro, map awareness... I don't know what to do, it feel so crazy going from that win rate to practically the other way around in a few days.

Thank you for reading this, I will appreciate every message.