Love is something that is very powerful and can be for the best or worst of many guys.
If you look back on Greek Mythology, all the gods (even Zeus himself) were afraid of one other god... Cupid (I think his greek name was Mercury, but I may be wrong).
Love can make a man do things he would never do within his right mind. It's something that can invoke tons of different other emotions, some you seem to have already listed. Powerful emotions such as greed, lust, and jealousy. It can make you see a person as someone else entirely, whilst you are unaware that you are ignoring any bad things that may be true.
Take this for example. Let's say you hate weed, with a passion. You hate the concept, you hate people who smoke it, people who deal it... you pretty much hate anyone who associates with it in the first place. Now you fall in love with this girl for a long time. You're still just the friend who secretly has an enormous infatuation with this girl. But then you find out she loves weed, and smokes it all the time. All this time, you had no idea, and now you find out.
But you'll ignore this fact, or even worse... adjust your mindset to accept weed. You wont exactly smoke it or anything, but you no longer hate it, just because of this one girl.
I think thats something very powerful. Love can change you as a person, your beliefs, your way of living. It's no wonder why Cupid was feared most by many.
.
Now I can't really help you out here kid. I too have been down a similar path that you are on, and I cant exactly say I found my way to paradise. What really happened was that I often became lost and desperate trying to find that perfect destination. I never did though... I went off the bath, abondoning it and its endpoint. At first I was lost for a long time. I thought I was going to be lost for an eternity, but luckily I stumbled across a new path.
The trick is to keep going through these little experiences (for it will happen more than once) until you find that path that you know will lead you to what you want. And once you get there, it truely is a beautiful feeling.
So I would say to break it off with this girl as many other people have already suggested. I hate to sound cliche, but there ARE plenty of other fish in the sea. I'm sure that sooner than you think, you'll find another fish where you can go through all of this again... hopefully finding your happy ending. Sorry about what's going on, but all I have to say is that you still have an entire lifetime ahead of you. This will not last forever, and you know that, so chin up ok?
Thank you for your time.