I want to talk about levels in poker, especially a psychological level, not about the math. Whether playing poker shortly or you are an experienced grinder, your confidence will have a huge impact on how you play and access every session. Your bankroll will go through natural cycles of variation, but time is improving the quality of your game. In general, I can say that from my own experience, the most vulnerable times for the game confidence are the times when we catch the downswing, but it may also be when we go to a higher limits, changing the game, or move to another playroom.
When you are not playing your A game, it can be due to a number of reasons. However, to be confident or believe in yourself is very important  in the game of poker. Without confidence your play is scared, you are hesitant and more prone to tilt plus you keep the negative thoughts that will affect the logical judgment needed for a better game. Having faith in your abilities will help you keep your head upright, even during difficult times and prevents you from guessing.
Even experienced players can have doubts of "those games are no longer what they used to" or "it's less FISH and maybe my style is not working as well as ever"; but in fact they are probably wrong. Although it is important to adapt and make changes, it is unlikely that the changes of the game happen in such a short period of time. And from my point of view, if you do not make effort to raise your self esteem, it is nonsense to make any drastic changes in your game.
Problems with self esteem often lead to the fact that the players cease to make healthy risks and start to play scared and afraid to make mistakes. Of course, the goal in poker is to make fewer mistakes than your opponent, but oftentimes, if you do not play aggressively enough for the pots, that is the greatest possible mistake. What I'm trying to say is that you had better make mistakes aggressive than conservative. Build your mental strength to a level in which you are able to maximally utilize your smart aggression.

Enough for now.

Stay cool, stay in school, rule.