ok, lets take one bit of your thinking at a time here.
re " I know she wasn't perfect, but she was perfect to me." maybe, but if you were perfect for her she wouldnt act like this. It is a two way thing.
"Since she's cut me out, my confidence, self-esteem and
self-worth has taken a nose dive and I keep tormenting myself with "what
ifs" and "why did this have to happen" type scenarios. I go from bawling my eyes out
to becoming down and depressed and not knowing what to do with myself." How are you going to go when a close family member passes on? For you are not only describing the loss of a "potential" girlfriend, you would be posing a close person you've known and loved all your life that has died.??
"She was everything I could ever want in a girlfriend" Everything? So your dreams of the perfect girl cuts you off and refuses contact? Perhaps the "perfect girl" in your mind is like her but with improvements...big improvements.
"The only thing my friends have told me is to just suck it up and move on with my life," Yes, because that's what the average person does. You are LC, not them. Sometimes the last people you ask advice from is people not emotionally involved or not qualified to comment.
"I'm in love with her and I want to be loved" Want to be loved? means you know you were not loved by this girl. Your love for her IMO is infatuation and puppy love. That isnt meant to hurt you, its meant to clarify it to you. Also bare in mind- for some this kind of love is only ever replaced by the love for another girl. Thats why its important to move on.
"This may sound weird but I feel if I met another girl it would be cheating on her in a way" Thats because you are thinking unrealistically. I've felt this way myself a few times when young only to find the girl was seeing another guy all along. I was wasting my energy and thoughts for weeks...wasting my life away.
It has come to a point now LC that you need professional help. Unless you can divert you thoughts with the help of hobbies, sports, mates, etc then you have to seek the advice of a doctor and seek therapy. I am with you on this, I know how you feel. I've been there. But not only are you not able to move on, one day in the future you might meet another girl and you'll feel the same way and WHAM.. As I said before imagine if you married and had kids. Your whole world comes crashing down as well as your future..
You havent got the tools to deal with this. Tell this to your parents