Mental health?

Hello, so I've been having some issues lately.. The past year my moods have drastically fluctuated from being happy and glad to being depressed and contemplating if I even matter. They aren't like extreme manias and such but the moods switch a lot and there seems to be only a month of normalcy... I'm concerned what's wrong because it's not on a hormonal cycle it's just random and I can be depressed for 3 months then happy for a week then neutral for 2 weeks happy again ten depressed and so forth... It's really taking a toll in my relationship what should I do? Seeing a therapist is out because of the price and I'm too embarassed to ask my parents for the appointments (very old school style). Help?