Hi, I understand your concern with the weight gain. Most likely it is because of the tablets , as you exercise and do Yoga regularly.
Talk to your doctor about your concern, he/she can then change the tablet to something that does not cause weight gain.
Just rule out Hypothyroidism, in which weight gain may occur , by doing your
Thyroid tests.
In the meantime, focus on your diet and maybe increase your exercise .
Keep a diary or use an app to track your intake and daily output.
Do not panic and start ayurvedic tablets, unless your doctor permits you.
Hope this helps, All the best!