Don’t worry, three weeks is nothing. You’ll get updates at some point, but there’s nothing urgent about them.
As a spousal sponsorship applicant you can’t be deemed medically inadmissible on the basis of excessive demand to the health system. This exception doesn’t apply to any other class of sponsorship, however.
The only way you could be medically inadmissible, as far as I’m aware, is if you have a communicable disease/illness that could pose a threat to others in Canada. On that basis, there’s not much someone being sponsored as a spouse could fail a medical on.
Relax and await the next stages of the process.