When guilt becomes a curse

Sometimes I feel guilty over the smallest thoughts. It could be something as human as thinking something a little mean or judgmental, but the guilt hits me instantly, like I’m going to be punished for it. As if the universe is keeping score and saying, “Aha! You weren’t nice there, so you don’t deserve to get into the school you applied to.” (example)
I apply this mindset to everything. It’s like I’m holding the whip myself, giving myself anxiety just for having completely normal thoughts. I know it’s human to occasionally have unkind thoughts, but the fear is still there, that I don’t deserve good things if I think/say bad things.