Your appetite will come back eventually. I imagine the breakup was pretty traumatic so you're probably in a pretty rough state right now exhausted, hyper-vigilant. Umm in the meantime you could try liquid meal replacements. I used to have bad anxiety I couldn't eat either, no appetite, literally couldn't eat, my throat would close up, I'd feel nauseous and feel like puking, etc. I didn't want to deprive my body of nutrients too much so I went for liquid meal replacements like Ensure for a while till my appetite came back.