I've been on Advair 250 for about 6 months now and have gained a...

I've been on Advair 250 for about 6 months now and have gained alot of weight. I don't have any throat problems, as I was told that you must rinse your mouth after taking the medication. The last week, I started to think that it was the Advair that might be causing the Weight Gain that is causing me to feel Miserable!!!!!! How do I get off of the Advair. I read that you just don't stop it, so I gather that you have to wean yourself off???? Karla