When your mind is blowing things out of proportion and you know it's wrong, how do you convince youself?
I love your picture, beauty. Super cute.
If you know you're blowing things out of proportion when you're in the act of blowing things out of proportion, you are miles ahead of
many people. That is a gift. So don't squander it.

It's OK to stop, remove yourself from any situation and say you need a moment, and then go and breathe or meditate or run or journal or anything constructive and solitary that will help you get back to a balanced place. This is a discipline. It takes a few times of consciously stopping yourself before you learn to practice it with ease.
And this is just based of some of my recent experiences, but maybe you're not blowing things so out of proportion? Maybe it's just that your response isn't appropriate? Don't second guess your feelings. Your feelings are your feelings. It's what you do with those feelings that might need adjustment.