I think that everyone is shitty in some way--or has been to someone at some point of time in their lives. I'm often considered a bit of a saint in my friend circles because I go way out of my way to help everyone, but naturally that stems from the type of insecurity or need to please people that causes me to (guess what?) be shitty to people who are close to me too. I'm not great at boundraies. I'm clingy. I'm human and a work in progress, as everyone else is.
So if you're working on these things too, self-reflect and all, but don't take it as a verdict on who you are. Doing shitty things doesn't make you a shitty person. It makes you perfectly imperfect.