Depression.

I've been fighting depression on & off for the last few months & have no idea why. I got married in July & since then I've been having a really hard time with myself. My husband says its once a month & he thinks it's me PMSing but I haven't had a period in almost 2 months. Does anyone have any advice for me? I'm normally a really happy girl so it's very frustrating that I'm going through this in my first year of marriage ?