"Love" advice? help please

earlier this year I started talking to this really cool, intelligent, kind, artistic guy. we really connected like right away but there was a slight problem: I'm 16 and he was 18 going on 19. obviously romantic relationships like that are illegal so we just decided to be friends. so anyway we take up the "just friends" label but the feelings don't go away. this guy is the first person in my life to listen to what I have to say and appreciate my mind and be open with me about their interest with me and all that. Words can't describe how blessed I feel to have has this boy in my life. I'm pretty mature for my age and he always commented on that. like he said that if I hadn't told him I was 16 he's probably assume i was in my twenties 😂. but we both felt a very real, strong romantic connection. he mentioned me in a song, referring to our love/creation of art and how he was fed up with the limitation of the age gap. like how many girls can say they had a song written about them at 16 years old? man he was a dream. problem is, he came into my life when I was on medication for my poor stated mental health (I have severe depression). Normally i can handle my minds faults in my social life pretty well I guess. but the medication always made me feel dazed and far off from reality. so with that and talking to him, I missed all the signs and fucked up the conversations a lot. I killed the romance and didn't realize it until months later when I got off the meds and all that realization hit me like a ton of bricks. now he's got a girl. and she's fr fantastic and beautiful and charming and sweet. she is every thing this boy deserves and more. there's no way I could possibly bring myself to hate her bc she's just so perfect. I'm happy for them fr, but I still really miss this guy. we don't talk any more, it's like we never knew eachother in the first place. I want him back in my life soo bad and i don't know what to do. no matter what I can get over him. everytime I try I just fall for him all over again. I need advice. I have no idea what to do