I feel like I'm getting worse. Is this possible?

Hi, I've been playing chess for a long time (not on chess.com), I've had coaching, played lots of puzzles, etc. Because I hadn't played in a year or so, I decided to get back in to chess with chess.com. When I started playing on rapid, I was first given a rating of 850, which frustrated me, because I often play with people who are much higher (1200, 1300) and often win. My rating has been in a steady decline though and the mistakes I noticed 700 players do when I first got that rating, I'm not even noticing anymore. I used to have the advantage in the openings and middlegame but just blunder somewhere in the endgame. Now, I'm just constantly losing. This is really frustrating and I'm getting stuck. Is it possible that I'm actually getting worse?

You only started playing rapid here a few weeks ago. I would wait til you have been playing it longer to start speculating about a cognitive decline.

I looked at two games you played today. In one you lost to a back rank mate. That is something you should pretty easily see at an 850 level. Have you tried Puzzle Rush (timed)? Seeing one and two move mates can be trained.

In this one, you also ignored an opponent's threats:

You haven’t played in a year. That’s not just rust—your brain needs time to rebuild pattern recognition and recalibrate.

Me too. A bit

I stopped playing a couple of months ago so now I think I have to divide my last rating by 2

Does my daily always start with 100?

Improving Your Chess - Resources for Beginners and Beyond…

https://www.chess.com/blog/RussBell/improving-your-chess-resources-for-beginners-and-beyond

Thanks everyone for the advice!