Can I Ask A Doctor For Help On How To Improve My Sleep Patterns As I Have Serious Sleeping Problems ?

I am an 18 yo female college student, who has a serious sleeping problem. My sleep schedule is really messed up and has always been and it is messing with my school life. I can only sleep in the day and not the night. On days I try to sleep at night, I am awake, and I can not sleep, because I have a lot of worries. I can only fall asleep when I am tired and not thinking. When I am sleeping I can not hear my alarm clock go off. One time I passed out for four hours, and my roommate said she was worried, because I was not responding to anything. She also told me that I snore a bit, and sleep talk sometimes. I really need help.