Depressed

I'm 3 months pp and I feel depressed. My husband just finished bootcamp and now he's at he's tech school. I love my child and I love being home with her, but recently I've felt like I want to get out. I haven't gotten out of the house ever since she was born. All I do is stay home and it's really getting to me. My husband starts school and has made lots of friends. I don't have friends and I just feel myself getting depressed more. I sound childish I know, I just can't feel like this all the time. Any tips on coping with this?