Are there significant up and down phases when learning chess?

I went from a 650 down to 500 over the last weeks. I am getting really frustrated. When I begun I constantly went up in rating, playing 15-20 games a day and winning around 70% of them. I then started to study chess openings more in detail and suddenly became worse and worse. I knew how to respond to various openings before I began studying in detail, but since then whenever something is played that I’m not used to it’s like I’ve never played chess  https://vidmate.onl/ before. I start doing things like hanging a rook or even my queen and end up having to resign after 15 moves because my opponent is up 8 points. When I started I didn’t rely on theory that much and somehow found a good move but now I’m playing like an idiot. Now I lose about 70% of my games. What happened or what am I doing wrong?

@1

"I then started to study chess openings more in detail and suddenly became worse" ++ Normal

"hanging a rook or even my queen"
++ Always check your intended move is no blunder before you play it.

"I didn’t rely on theory that much and somehow found a good move" ++ Normal.

"what am I doing wrong?" ++ Do not study opening theory, apply opening principles and think about your moves. That way you reach a state of concentration and you understand the position, as you have constructed it yourself.

Absolutely. Some people notice a drop in elo while they're doing puzzles or working on building new habits. That's how learning works: the brain has to expend less mental bandwidth on fundamental processes so it can learn a new skill. But once that skill is automated, it stops using short term memory and is integrated into long term, and the other processes get the original energy they were given prior to learning.