How do you get over someone you still love?

What surprised me though is that, after telling him yesterday, my feelings changed from determination to end it to suddenly feeling a sense of loss and even hurt. I'm not sure if that me feeling bad for hurting him or if I have a genuine feelings left. I fluctuates from hour to hour.

Probably both. Just because you aren't happy with something, doesn't make it any less a part of your life and the loss, intentional or otherwise, of something that you once loved and was an contributory element to who you are isn't going to pass unnoticed emotionally. And yes, you probably do feel guilty for hurting him, not loving someone doesn't mean you don't care about them. Good news is, you're a perfectly normal human being, flawed, fucked up, unique and wonderful all at the same time.