Question number 1
You need to learn how to control your emotions. Emotions as we know are positive and negative, there are two sides to the coin ... Faith is a positive factor, I believe that this factor is very important for achieving high results. Such factor as doubt in success ... has a negative effect , and if it has a negative effect, then the consequences will be negative.
Question number 2
Games really affect our mood, if we take specifically "Poker", then after a drift (a big win for you) you will be filled with positive emotions (for example: Joy), and after a wave of losses (Downstreak) everything will happen differently (for example: Sadness) .
Question number 3
Not all have peace of mind - because it's very difficult to master the calm, especially after the big losses ... but luckily there are people of exclusion who are calm about losing (even big). If you lose, I advise you not to fight this loss, but accept it, since there are no defeats without defeats (it needs to be understood), if you lose a lot during a long time ... accept this, and try to stay calm (try to understand why it all happened, and not panic) ... Peace of mind You can only master strong people, and I hope that you will be one of them.
Question number 4
I agree with you, you need experience in order to have negative thoughts as little as possible ... It is with experience that a person becomes more confident in himself, when he has something behind him (some way) it becomes easier for him to look forward , thereby avoiding the negative.