How Do I Fix My Biological Clock ?

My sleeping times are a mess, it's like my body doesn't live in 24 hour intervals, it sleeps and wakes up whenever it wants.

Just yesterday I was really sleepy at 12 and I slept with no issue, but today, it's already 4am and I can't sleep. It's like this everyday, some days I sleep super early, some days I don't sleep at all, some days I sleep twice.

Maybe I should seriously consider getting some sleeping pills....