I spent a lot of time waiting for buses today, so when I finally got home (after some weird long delay on my bus ride), I had a bit of chill. While I certainly had an urge to crawl into pajamas and cover myself in blankets, I knew I had to go shopping. I slipped jeans over the tights I was wearing and had a revelation.
My body weight doesn't rapidly or randomly fluctuate. The reason why my pants fit for 6 months and then don't fit for the next 6 months i because I spend the winter layering them over tights.