Welcome by the way!
Molly all you really can do is be prepared for this to happen EVERY season change. Make a flare care package for yourself. Things that you know make you feel better, meds, heating pad etc. Make your doc aware that season changes also spike your FM issues. Maybe he/she can help you.
Just to let you know, you are NOT alone in feeling the weather. Just cope the best you can. I find pity helps!
Actually coming here helps because I know there are people who know what I am talking about and what I am feeling without having to totally go through the explaination of FM and what it does to the body yadda, yadda, yadda. If you feel that bad, call your doc and see what they can do. Otherwise I hate to say this but until the weather decides what it wants to do for good, you may have to ride it out.
Good luck and keep us updated!