Hi, Welcome to HealthcareMagic Forum.
You haven't mentioned your age and Gender? Anyways Masturbation
is a completely healthy habit and it is natural to feel exhausted after doing it as you burn calories. There is nothing you can do and just relax and take rest for 15 minutes or so for regaining complete strength. Take your Hypothyroidism
medications regularly and Maturbation does not cause any growth retardation. Do it only when you are sexually aroused.
You can do regular swimming and skipping if you want to increase your height.