Trance: Go ahead and take a deep breath. Expel. Repeat. Vent as you need.
Then stop, and put it behind you.
Yeah, it is trite sounding, but speaking from experience, and, mind you, I'm talking about a lot of experience. I've been in that boat before. I'm probably still in that boat every now and then. Proof positive that, no, it isn't easy and never will be.
Harassment sucks and I don't have much advice beyond this: the simple fact that they are electing to pick on you already puts you miles above them as a person. Take it however works best and let it slide off you. If you need to turn the other cheek, turn the other cheek. If you need to lash out, tell their sorry asses off, ignore the comebacks, go home and do something you enjoy knowing that, personally, you won.
You cannot go through life making everyone's problems your problem. It is severely unhealthy. If you keep doing it, you will end up like me, which is a phenomenally depressing prospect. The sad fact is that you will not always be able to help people with their issues. There are problems you can do absolutely nothing about, and you need to accept that, offer up a crying shoulder and let it go. You also need to realized that people around you, your friends, your family and your loved ones, have a responsibility to offer that same benefit to you. Don't be afraid to lean on them when you need it. If you're tough enough to deal with everyone else's shit when they are down or in trouble, then there are people around you who ought be tough enough to deal with YOUR shit when you need.
TL;DR: Learn to let things wash over you, don't internalize so much and don't be afraid to externalize.
Also, no self-deprecation. It is only funny when I do it. ^_~
