Chess giving me mental health problems. I quit.
The rating system is just a means to pair you with players of roughly equivalent ability.
Eventually you will get to a level where you are winning and losing approximately the same number of games.
Just accept this and enjoy playing. If you get hung up on the rating you will never be happy.
I've been there, too, and I know it can be tough. There's a whole world out there beyond chess, and it's fantastic that you're diving into it! Sports, dancing, Rubik's cubes – it all sounds great! I also wanted to mention the National Rehab Hotline for anyone who feels like they need help - https://nationalrehabhotline.org/. They're there to offer support and guidance if you ever need it. Take care, and keep on enjoying the adventure – both on and off the chessboard!
Although sometimes itself a source of stress, chess has often been a useful distraction and at times has kept my mind out of some really dark places.
Setbacks and plateaus are common in any skill development journey, including chess.
I'm going to get to 1800 one day... hold on tight 
1500 is an Intermediate - advanced player rating, not beginner. People who say 1500 is a beginner have no idea how the chess rating system works, 400 is a beginner. Anyways, You should play chess for the fun of it, not for the rating. The rating is meaningless. So, lets say you would reach 1800 now. And then what? Fine, you can say you are a pretty good chess player. But do you think its really worth this so much hard work?
Play chess for the fun of it, chess is not a chore.
it honestly depends on the site. im 1600 on lichess. (i dont play much on chess.com) but im not that good anyway