How can I deal with anxiety when playing this game? I feel like I cannot climb because of it.

Every time I get behind in this game I get very bad anxiety and I do not understand how to not do so. I get behind in game and then I know because I am behind I WILL lose because I cannot trust my team ever no matter what so I need to get ahead. If I can't get ahead that's when the anxiety ramps up and I know I'm going to lose LP with absolutely no way out of the situation because playing from behind you can't make any plays and the game essentially becomes "pray they throw". People will always say "it's bronze/silver they'll throw" but that's not necessarily true because both team should be equally matched so it'll still favor the team with the lead because even if a throw happens no guarantee other side will see it.

I have a negative win rate on every champ I play, I've tried watching guides, I've tried practice tool, and nothing works. I've tried changing champs and it hasn't worked and anxiety still peaks over and over. I've tried "playing safe" but then my enemy mid just roams and takes over the game despite multiple missing pings, and then they get ahead, I'm behind, no win con, my team loses. I really just want to be able to climb but I'm scared and idk what to do and nothing works. The summoner school subreddit is always very mean to me so I'm posting here. I am very desperate please help me out, I'm sick of this anxiety and being so low rank.

(and yes, I know relevant username)