Highest rank ive ever been I feel like im the worst ive been in a long time

This could be a couple things but I feel like im playing like im a gold plat player in diamond ascendant lobbies. I hit ascendant, a new peak for me and I feel like im a really bad player. Ive been filling every game because I dont have the confidence to instalock Neon anymore and I do mediocre at best. If there are any ideas you have at all, past just saying skill issue please tell me I really want to break past this.