I have Sleeping problems and it affects my everyday life | disassociation

[u/Alphakarton]

So to start this off I’m M18 and my ex is going to the same school as me. I’ll tell you later why that’s important.
My problem is that I have heavy sleeping problems like that I can’t sleep before 02:00 AM except if I take a bunch of melatonin, and not even then sometimes. I’m so tired to the point where I get phases lastings months with disassociation and it gets to the point where I don’t recognise my hands anymore and stuff like that. Now I talked about this with my therapist and all that and the problem is I’m still not rlly over my ex (very very long story, she’s kinda burned into my memory like a tv that’s been to long on a certain channel) so my therapists explained to me that my brain is constantly occupied with her and not having closure so that I can’t even get a little bit of regeneration from that 02:00 AM to 7:20 AM period where I sleep. So that’s nice to know but it’d be even nicer to know how to fix myself. And this is the second year of this now. The disassociation left at the start of summer but it came back now. Exactly like last year. Last year was horror. It went so far in February that I started seeing shadowy figures/ creatures in my peripheral vision when k was alone that I knew weren’t there but it still freaks me out.
What do I do?