The Pill and Depression

Molly
Hey everyone, I was wondering if anybody could help me with this problem:
I've been feeling really down recently, really lonely and sad and helpless.
I assumed it was just due to the stress of school and friendships and relationships and stuff but I've thought about it and I'm wondering if it might be some kind of depression brought on by the pill (I'm on Microgynon 30 ED).
I've been on the pill for a long time now and only over the last 2 months or so have I been feeling depressed, so that makes me wonder whether it's the pill or just my actual life! I can see why I would be feeling low as I've gone through a breakup about 4 months ago and seeing my ex at school is still hard, I'm having some boy trouble with a new guy, I feel like I'm too distant from my friends, and there's a lot of pressure going on with A Levels and University Applications. Nevertheless, I just feel like my sadness is stretching beyond those things and might be blowing them out of proportion. Basically I can't tell if my 'depression' (I don't want to exaggerate if it's not as deep as that) is induced by the pill or not and I was wondering if anyone has any guidance as to how I can differentiate or what I should do!
Sorry this is so long and complicated but I would really appreciate some help! 
Thank you xxx