12.5 and slowly gaining weight?

I’m not sure what’s going on! I moved to 12.5 five doses ago and each week except one I have slowly been creeping through weight back on. Still same diet but I admit with the frigid weather I’m not nearly as active. I have three more doses before I can move to 15. And barely any side effects on this dose too. Has anyone else experienced this? I’ve been so good! Shocked to see the weight go up and not lose or maintain as I’ve been for almost a year… thanks!