I Recently Over The Past 6 Months Have Lost Over

I recently over the past 6 months have lost over 35 lbs and I keep losing. My obgyn stated my weight before delivery was 157 lbs. after my pregnancy she got worried because three months after birth I lost 12 lbs then I lost 15 putting me at 112 and now I am border line running under 100lbs. I can't afford to loose anymore. I had blood work don't with my family doctor everything come back normal. And I still struggling with my weight I balance my meals exercise, I am all about keeping my body healthy. Just the weight scared me because I had this happen before just had my gallbladder removed when it burst. My last test I took for blood work was the TSH it showed 1.09, but I am normal just not for sure why I am loosing weight so fast. Do I need to take another TSH test. Everything else was normal. I am still trying to hang on to the the routine I have, but I just don't want to get back under 87 lbs. again. I took me a long time to get back up to a weight I am comfortable adjusting too.