help about love

I've loved I guy for a long time now. long story short he's ignored me for about 2 years and we used to be best friends I've loved him for as long as I can remember. I can't get over him no matter how hard I try. He doesn't love me I know for a fact and idk I just want to move on but he always pulls me back in. Everyday since I've lost contact with him I had a really rough time and went through depression and I honestly just can't imagine myself without him it may sound insane but.. any advice ?!