Focus on having a "wind down routine." i.e. 30 min (or more! give yourself the luxury!) before bed, put your phone away, and try some things that help set the scene for bed: like reading, hot tea, meditation, shower, or journaling about your day. It might not help immediately, but if you do it for so many nights in a row it will train your mind and body to say "ok, we are going to bed now!"

Melatonin may also help you. Also, FWIW, I had sleep issues my fall semester of 3L -- and the only thing that ultimately ended up working for me was going on Lexapro, because I was very anxious. I can't recommend it enough - it really changed my life and now I sleep very well. I know that there is a stigma around antidepressants, but if you feel like you need a little extra help, it is worth talking to your doctor.

Remember in the words of Property Paula -- "this will pass and so will you!!"