WLS and birth control? (Yasmin)

Hello!
Let me give you a brief history before I begin.  I had RNY gastric bypass in 2/04.  I lost weight steadily through late 2005/early 2006 and then began re-gaining weight, slowly for the most part, but sometimes 10 pounds at a time for no reason.  

I have been struggling over the past few years with weight gain, for no apparent reason.  I've been following my diet (while not 100% certainly nothing to warrant the weight I've re-gained) and up until about 6 months ago (because of repetitive stress fractures) I was exercising at least 5 days a week for an hour a day.  My body was not responding in the least to any form of exercise or diet, I was continuing to gain weight while exercising, it was beyond frustrating. 

I've had some thyroid issues which have been diagnosed since my surgery and recently they've been under control (at least for the most part).   I had my thyroid checked when I began having night sweats and migraines sometime in 2006.  I had not had a migraine since before my surgery and had NEVER experienced night sweats before.  

Over the past few weeks, I began hearing a lot more about the birth control pill Yasmin (my birth control) and side effects/problems it was causing for people.  Last weekend, while busy painting my living room (I had nothing to do but think) I was still thinking about Yasmin and all of a sudden a light bulb went off.  I began Yasmin in late 2005 or early 2006 and that is the time my weight began to creep back up.  Was the Yasmin the cause of my weight gain??  

I began to do some research, and while weight gain is not a common side effect it is a side effect that many people experience.  There are also a lot of people who begin experiencing thyroid problems while on Yasmin.  There are a ton of other side effects, many of which I was experiencing, but I was passing it off as stress or my period or whatever.  

So now I am wondering if there are other people who have had WLS and have begun to regain weight are also on Yasmin and some other form of Birth Control?  Is this something that could be causing an unanticipated complication?  Could this tiny pill be causing me to feel like a failure and doubt myself?  Could it be nullifying the wonderful process that I put myself through?

Any insights would be most welcome.

Michelle