plateau

A little backslide like that is nothing to worry about.

Look at all the progress you've made since you started.

I notice you really haven't tried Puzzle Rush. I think it's a great way to warm up before playing.

thanks. ill try that

Is there an explanation of puzzle rush anywhere? i can't find anything.

Hey!  So first, congratulations on the huge progress you've made in the last few months.  Your improvement may feel slow, but since January you're up almost 400 points!

A few things to keep in mind:  First, rating fluctuations are normal.  If you've ever taken a statistics class (and if my guess is correct that you're an M.D. I'd imagine you have) you can think of your displayed rating as being a Bayesian estimate of an underlying parameter which you might think of as your true skill.  If your true skill remains the same, random variance will carry your displayed rating back and forth, and streaks, which are common, may sometimes carry it pretty far.

Thing about chess at our level (both of us in the sub-1000 rating range) is that the variance can be enormous.  Whether we see a threat or blunder a piece (or see or miss opportunities to capitalize on opponents' blunders) can be unpredictable, and can, by itself, win or lose an entire game for us.  So, our ratings will fluctuate a lot more in normal play than an extremely high-level player's would.

There are a few reasons you might have lost more than you've won over the past couple weeks.  First, after a large upswing (especially if driven by intensive study) it might be natural to let down your guard and relax a bit.  Of course, your opponents aren't getting any less challenging when you do this.

Also, though, learning and starting to apply certain principles may take you out of your comfort zone.  As an example, I started learning a specific black opening that had certain risks associated with it.  I lost a lot of games playing this opening until I got familiar enough with it that I understood how it worked and how games tended to go a little better.  Now, it's my highest win-rate opening.

Many new skills in chess can have that effect, including learning new openings, but also things like consciously playing more or less aggressively than one has in the past, trying to apply specific midgame principles or endgame knowledge and either misapplying them or just feeling shaky while doing so, or learning new tactics and being so focused on setting up a clever move that one just misses a key threat.

You've lost about 75 points from your peak, but if you look at my rapid history, I stabilized in January around 800, hit a peak of almost 860, then crashed to 736 over three weeks before bouncing back up to 909 before losing a few games and landing at 895.  Overall my win rate is net positive, but man!

The sometimes-polarizing Twitch chess personality IM Levy Rozman (Gothamchess) made what I feel is a good video about rating anxiety, released on YouTube a few days ago.  His basic point was that rating fluctuation is a normal consequence of active play, and unless one is going to reach a rating goal and stop playing forever, you just have to accept that you will have peaks and slumps along the way.

I'd worry more about a "plateau" when you're working hard for months and making no progress.  You'll probably get to that point sooner or later, as will I, but it's not now.

Regarding puzzles and Puzzle Rush, the puzzles (on the Puzzles menu) are meant to offer you chess positions to which you find the best move or series of moves.  You can play puzzles in rated mode, which pick from the entire range of available types of puzzles to estimate your rating, or you can play in "learning" mode which lets you pick particular types of puzzles.  Also, there is Puzzle Rush, which is a game mode where you try to solve as many puzzles as possible in a short period of time.

A recommendation I've heard from multiple strong players (including IM Danny Rensch of Chess.com) is to do puzzles in "learning" mode and pick particular types to study particular things.  If you want to work on simple tactics, you can, for example, pick the "pins," "forks," and "skewers" puzzles and just work on those.  Or, if you want to practice seeing checkmate patterns, the mate in 1, mate in 2, mate in 3 puzzle categories can be great to practice.  There are plenty of others too.

Puzzle rush as a warm-up may be great.  I haven't personally used it that way, but I have put some time in on rated puzzles, taking my time, or in learning mode.

     Two possibilities occur to me. One is the normal "hot streak and slump" trend of almost all individuals and teams in all sports. I'm sure you've noticed that in a long baseball season every player will have stretches when he can't seem to get a hit and other times he tears the cover off the ball for a couple of weeks. It might be biorhythms, psychic ups and downs, planets out of alignment, whatever. Everybody has good days and bad days so you may need a greater number of games to find your actual average.

     Or it might be that you have improved your overall chess ability and have started to see and/or understand facets of the game of which you were previously unaware. Integrating these new ideas into your play might take some time, and make your play uneven in the interim. But when you have thouroughly absorbed the more advanced ideas you will play at a considerably higher level.