Why can't I love properly

Is it actually natural that I hate someone so much for loving them just as much? I wanna hug them until a piece of them becomes mine but I also want to destroy them to bits. Is there a thing behind this or am I just thinking of something that isn't even that deep and in fact pretty normal?

I just don't think I can deal with such emotions with the required maturity and calmness. Now that I think of it, I don't even think I have even ever loved someone in an actual way. I get filled up with these complicated emotions until I find something else to live off and the person I once "loved" means nothing at an instant and I get agressive when they get emotional. I have started to feel like I am a parasite that sucks the blood off of someone and gives some back at times so that the person never realises they are being consumed and just keeps coming for more. My internal hatred for myself and for being vulnerable enough to love someone brings out the agression in me perhaps. I just can't figure out why I am so strict about finding such feelings vulnerable since I grew up as an emotional person and still am. Oh, now I realised, awesome.

My emotionalness has always been an issue and I was always told to not show any weaknesses to others because they can use me. I have always heard "you are so emotional" in a very judging tone so I thought it was awful. Emotion meant weak. Emotion meant losing. Emotion meant loss. And while I can still feel all the other emotions properly, love is not one of them. I have no idea how I switched to that when I have never been judged for loving. Maybe it's because I grew up unattractive and still think I am not worthy of being loved, so I automatically think that I won't be loved back. However, I have been loved back and even loved more many times. 

At this point, it is just painful. I just want to love someone purely.