Boyfriend leaving

So my boyfriend works 4hours away for 21 days and he works 13 hours a day. I have major depressive disorder and it gets so much worse when he leaves for work because I am alone. I moved in with him a month ago and I have no friends here, only him. I get to talk to him maybe an hour out of each day because he goes to sleep so early. I can’t stand the feeling of being alone, so when he leaves my brain makes up all these different scenarios and thoughts and I just cry all night. I don’t know what to do about it.