In two weeks my pants have gone from fitting me fine around the waist to not fitting me at all. When this happened I checked my weight and I weighed 20 lbs more than I typically do. I don’t think I’ve changed anything in my eating, exercising or sleeping that could cause this. I’m not taking any medications, so that isn’t the cause either. I’m a 29 year old ectomorph. I included pictures that I took of the changes. I don't think my photos look like someone whose waist has gone from a 32 to almost a 36 in a few weeks. This weight gain was so sudden, and so different than anything I've experienced that I'm concerned that there might be a larger medical issue behind it. If anyone has insight on what could have caused this I'd greatly appreciate it.