Yup, ok, that's like trying to sleep on extra super difficult mode. Follow all the advice you like on here, but definitely get yourself some sleep meds. A therapist can prescribe them for you, and they're typically easier and cheaper to find/schedule than a regular doctor.
Like a studio apartment? Maybe it would help to have a "daytime setup" for your bed where pillows and cushions make it more like a couch, and a "nighttime setup" where it's made up to sleep.
To add to this. If you can't sleep after about 15-20 minutes get out of bed and do something to relax your brain. Reading or meditating works well. Definitely no phone or TV, don't read anything captivating. Read something boring you aren't into. After you feel 'sleep pressure' go back to bed.
Over time this helps your body associate the bed with just sleeping. But it takes time and dedication. Find a routine.
Also highly recommend always going to bed and getting up at the same time, even weekends.