firstly, i'm an 18yr old girl and my height is 160cm (5 foot 2 or 5 foot 3? idk but im 160cm)

about 2 weeks ago i was always 53kg (116 pounds) everyday and then i gradually became less and now i'm 50.5kg (111 pounds)

I haven't been doing any exercise BUT i did become vegetarian on the 4th of November

&

I take one thyroxine tablet every morning since July when I was diagnosed with Hypothyroidism which made me gain weight. But that did nothing since July so why am I losing weight now? and my thyroid is still underactive

If it helps, i've also been like sleeping at Midnight or 2am and waking up at about 1pm

I really haven't been exercising though, but i should coz my thighs are really fat and my stomach sticks out like im 3 months pregnant!!!

and my BMI says apparently 47kg is the lowest to be healthy weight, so how can i even lose stomach fat without going below 47kg??

thanx for your help!! best answer gets 10 POINTS :) ♥♥♥