Weight gain causes may be depression,insomnia(sleeplessness),steroids overuse,
kidney disease,Alcohol consumption,
diabetes,certain medications,sedentary lifestyle due to Pandemic and work from home situations and also hypothyroidism but as you mentioned you have checked your
thyroid levels which are normal so need to rule out the other causes.
Next Steps
Please feel free to contact me for discussing your case
Health Tips
Do yoga daily, Meditation, take relaxed walk 20 mins after every meal for 15-20 mins, Avoid lying down after meals, Have salads and soups take bhakris instead chapatis, Have protein rich diet.