From my time at weight watchers, ive heard that people can hit a plateau, where, after steadily losing, their weight will remain the same for several weeks or months. They are advised to stick with it, or "switch something up" - try eating more, try exercising more, eating less of one kind of food and more of another, idk what all.

Also re stress - it makes the body produce cortisol, which makes you put on belly fat, regardless of calories. Its like it just shoots fat to your belly.

Also, re your meds changing, you may be losing fat and gaining muscle (which weighs more but takes up less space), so why dont you take your bodily measurements? Didnt you say your clothes were getting looser? Your waist measurement may be a better indicator of your fit or fatness.