I'm in a slightly similar position, but in other ways its very different.
Around 8 months ago, my ex and I split up, we were together for 18 months and were long distance. It has since become very clear that she used me to get dating experience but without being in a "real" relationship. Even if that wasn't her conscious intention. I don't want to delve into all that too much, but the point is, she ended things back then.
The past 8 months have been awful. I have no desire to be in a relationship with her, but I miss her dearly, or maybe the way I felt around her, maybe both. I struggle sleeping, I struggle with motivation and it takes so much energy to mask around other people and just do the little things in life.
Now, I don't know what to do. I sit somewhere on the asexual spectrum and to me romantic love is something very special. I just don't magically stop loving someone and if I love someone else like that again, I'm being unfaithful to the original love, which has it's meaning diminished as a result...
I'm only 20, so I'm probably very naive and maybe I'll only ever be able to move on when I find that person who makes me feel that way again. Or maybe I will never be in that kind of relationship again.
Clearly I have a lot to work through, but my advice is simple. Look after yourself. Care for yourself and put time aside to heal. Do things you enjoy, cook your favorite foods and put yourself first in every action you take.
Sorry for the long message, just wanted to add my two cents. I wish you all the best OP.