depression?!?

I think I have depression. I have two kids under 3 and I'm just always so sad and moody my bf and I are always fighting and it's just making me so much sadder (I know it is due to my moods that we fight but I just can't help it) I try and be happy but it will only last a afternoon or something. I don't know what to do. I feel so old and like my life is so crap I'm only 22! Has anyone taken anti depressants on here???? Should I take them?? Plz help