Breaking The Cycle

My sleep schedule has been super wompy lately. Instead of sleeping at night like I normally should, I stay awake all night and sleep from about 7am-2pm. I have a lot of anxiety about falling asleep at night and that's what mostly keeps me awake at night and prevents me from falling asleep. I've tried fixing it by pulling all nighters and trying to stay awake all day on my days off, but I usually end up taking a small nap and all my progress goes out the window. I'm not sure what to do. I already take melatonin supplements but I feel like all the anxiety I have about falling asleep tends to override them. What can I do?