You're definitely not bad if you love all the people who have been in your life. Who knows, maybe being on the outside gives you a clear view of how others are really acting, while they don't have a clue.
Also, if you treated that person in a way similar to how they treated you, then don't feel bad. That's just nature to fight back and protect yourself. There are a lot of abused people out there who let themselves go when someone starts attacking them, and it only increases the behavior. It's great that you feel guilty, though. It means it wasn't in your nature, but just something unusual, or you felt you had to do. Don't let the way he treated you or spread information about you make you feel like you're lower than him. It's great you're being the bigger person here and know that what you've done was wrong.
As for bad things, I think every person has done at least one great bad thing in their life, even those who seem extremely perfect. I've heard some bad stories in my life and I honestly forgive a lot of those people if they changed their ways.
Another thing is that maybe the people are making your problem out to be over-exaggerated for their own fun... I've had this happen to me to, and starting to hang around new people was like the opening of a curtain I had forgotten was there. Suddenly-daylight! The people messing with your heads don't know what it's like in your shoes, after all.
Either way, I'm sorry to hear of this... I had been feeling similarly too lately, but from different problems. Reading your post made me feel not as alone in this. One thing that helped was telling myself that I would just see how the week will go and not put on such a fake look and attitude I usually have. That helped lift a lot of weight off my shoulders.