Forgiveness??

Most of us have been hurt bad by people. Whether those people are people we loved, still love, friends, best friends, or just the bully kid that used to torture us in high school. Then time passes while you're away from those people and we feel we're ok again. We meet those people again and suddenly it's not despite we bring ok about it just a few minutes earlier.
You'd definitely sense it in case you ever have to extensively deal with an ex. But it makes me wonder: what's the difference between forgiving and letting go? can you be ok with something that hurt you without forgetting it? better yet, can you be ok with the person who did it? but if it's big then it probably cannot be erased from your memory, does that mean you can never deal with that person again?
if it's so, then why the hell can't i stop it? in my case, i can't forget or stop feeling bad about anything she's done to me, yes we broke up, but still, we deal as friends and all that but something about this dealing just feels ... erm ... weird! I can't say i don't have feelings for the person, yet i can't say that i feel that ok about her either. It's a really weird love/hate mixture, and i really don't know where the hell am i going with this...

anyways... over'n'out