I took a break for 3 days after the act ended, I returned and got diamond 1 but I was playing so bad and I still am, I don’t know why either

So I'm currently on 0.22 sens with 1600 dpi. I feel it's pretty good for me and I'm on ascendant 2 with some quite good performance. The only issue is after some rounds or maybe games, my hand starts getting tired and my performance gradua...