Do you stay at home all day? Is that why you can get away with sleeping through the day? That may be part of the problem. Not having that push to shift your waking moments to daytime.
I used to have such issues. Not so much anxiety. But I would stay up all night. Reach a stage where I was no longer sleepy. Then stay up all day. Then all night again! But after a couple of days, I end up crashing in the day. Still staying up all night.
You’re probably best to tire your body and mind out during the day so you crash at night instead of during the day.