clothes don't fit

All my 16/18's are way too big now. My 14's are starting to get too big. I have one size 12 that I am starting to fit into. All my other smaller sizes I gave away. Now I wish I hadn't, I don't want to buy 12's if I'm going to be in a smaller size in a few months. Hard to fit into pants right now and too cold to wear skirts.