It could be the pills themselves causing both the weight gain and the emotional changes. You said this is only your second cycle on them? That would be my first guess. Sometimes it takes a couple of tries to find a pill that works for you. Are you on metformin as well?
Yes, you can stop taking the pill mid way through. I did it because I started on Femcon and it gave me Interstitial Cystitis (feels very similar to a urinary tract infection), and it also gave me horrible headaches. I stopped about 2 weeks in. You have to wait til you bleed again to start something else, but it certainly can be done.
I'm sure it's the pills - I mean weight gain and emotional/hormonal changes are STANDARD side effects - even with women WITHOUT pcos!
The only other time I experienced something similar was when I had a grapefruit sized cyst. I'm sure this is not the case with you, because you are on the pill (I wasn't). I gained 10 pounds in a MONTH and my hormones went completely NUTSO!!! I was an emotional wreck and breaking out and everything. Those cysts can really do a number on our bodies! But I really don't think that is it for you - I was in excrutiating pain when I had it, and like I said, I was NOT on the pill.
hang in there! I hope you start to feel better!
This sounds like a question for your doc! Good Luck!