How do you know if you're a fuck up?

I'm sorry to ask a bunch of strangers this question, but it's all I have left. I feel like everyone in my life looks at me like a fuck up. They never say it, at least not all of the say it, but I can tell in the way they talk to me... the way they look at me... I don't know what to do.
How do you know if you're a fuck up?
Post Opinion