Feeling down, but only at night. ?

I just decided to move back home from Florida to California because of school. But now with only 4 days left until I leave and only having one more major thing to do before I'm good to go home I'm feeling really depressed and sad at night. It's only at night. I dont know what is wrong and it kind of scares me. I know that I will be fine when I get to the airport Thursday and head home but I dont wanna keep crying at night until that day. Any advice?