Weird mouse thing, not because of my mouse its the game

So I have this problem that whenever I join in a game my mouse doesn't do things that it is supposed to do like when I'm on free cam and I try to move it around the edges on my screen nothing happens, and when I try to buy things from the shop nothing happens either unless I click it atlas 20 times, same with using abilities, I can use anything. The only way for me to fix it is to leave the game and reconnect but with my slow computer, by the time I get back in I'm already at least 2 levels behind. I don't know why when I reconnect it fixes it but I need help, I can't have any fun because in the lane I'm in ill just get destroyed. I have already tried to delete LoL and re download it, and that didn't help. Someone please help me with this.