need advice, been ghosted and lost a great friend

I (23f) met this friend (24M) in medical school, where I got into a different group of friends and he'd be one of the "odd one out" in that everyone found him unusual, as I did, since he's not like anyone else. I felt I'd fit right in at first but then realized I didn't and I met him, which was a relief because I'd think "oh there's at least one other weirdo like me". We started talking a lot, he'd ask me if I could smoke around him (I'm a heavy smoker) and I'd always say yes, he'd always say hello, I'd SMH thinking he was just being friendly, but he's asked me different things until I finally had enough and asked "why are you like this?" and he revealed he'd liked me for a long time, but I didn't feel anything. I didn't think it was weird or anything and at that time I was reading a lot of random things about spirituality that said the energy of the mind is everything, and I liked him enough, so I thought, hey, why not, God chose us to be together, he's fine, he's nice, why resist that? So we started dating for real, and I didn't even realize how much I cared, how much I'd want everything to go right for him, how much I'd think about him, and he'd make favors for me or get me presents and I'd feel the happiness in my heart and think "oh ok, then I guess I'm in love" because I didn't understand what it was like, until now, where I miss it so much it's very hard to live, and I feel lost and so alone, and I miss him. I miss him a lot. We had a falling out months ago that I don't understand until this moment, I remember he'd cut himself and I'd ask him to stop, and once when he talked about being so sad and I told him "maybe you should talk to someone professional, I don't know how to help, this is beyond my capacity" and he'd be angry and say "I don't care about anyone but you, I only tell you" and I'd think "oh, maybe he'd eventually get better" and then he'd say "you're too spiritual, you don't live in the real world, you don't know what it's like to be different" and I remember he'd cut himself and I'd try to stop it and he'd say "stop helping me, you don't care, you don't care about anything but your spirituality" and I think now that I should have listened, because now he's gone, and he's left me like that for a long time, and I don't know what to do. We had a huge fight around my birthday and he said a lot of ugly things he didn't mean like "you're not my girlfriend, I'm not dating you, you're not someone I'd care about, I don't want to date you anymore" and I believed it, I don't know why, I thought I'd been wrong about him caring about me, maybe I'd been wrong all along, I thought. But he didn't talk to me for a long time, and he didn't even wish me happy birthday, which I thought was a message, and I had to be the one to reach out and talk to him, even when he'd say he was so sad and different and wanted me to care about him. I remember he'd cut himself and say "I'm sorry, I know it upsets you, I'll stop, I love you" and I'd say "I don't care about that, I care about you, please don't, I love you too". I remember he'd try to die and I'd take him to the er and sit for hours for him to get better. I remember he'd try to die in a different way and I'd take care of him and he'd be grateful for me. I remember he'd say he was so happy that he met a person who actually cared about him and I'd say "I love you" and he'd say "we're happy and we'll be together, forever". I miss him. I remember he'd get home and he'd hug me and kiss me and he'd look in my eyes and I'd see how much he loved me. He'd always say he loved me. I don't know what happened to him. I don't know why he left. I miss him very much. I feel so alone, I don't know what to do. No one else is him, and I don't care about anyone else. I miss him. I feel like crying. I love him. I miss him so much. I wish he'd be here. I miss him so much. I love him.