Hypothyroidism and weight loss in pregnancy

🙋‍♀️ so my question is ,i have hypothyroidism, I am currently pregnant with #2 and have lost 23 pounds. After my first born I tried everything from walking to diets and the weight is just falling off. I just started my hypothyroid meds when I found out i was pregnant (i was managing it with vitamins); is it normal to drop this much weight? I also only walk when weather is warm because my son comes with me. I haven’t walked much in a week because of stomach bug, has any other moms had hypothyroidism and experienced this