Hi Michelle,
Welcome back to W.I.S.H. sounds like you are off to a great start.
I know where you are coming from in a way. I've had back problems too! When I was eleven I had a back operation (I had curvature of the spine). Since, then any little slight change in the weather I feel it but I am not going to let that get me down.
I actually have to watch my weight pretty closely....I can't gain too much because it could jeopardize the back operation that I had...It might mess it up. So I try my best to keep a balanced diet and exercise at least 3 times a week.
I wish you all the best! You can do it!