Hi. That's good your meds have been extended. That's a good sign
Below is a related write up
Expiry, re-meds and extensions - If the medical results are about to expire then you
may be asked for a re-medical examination, if required. If a re-med is not required then the medicals will be extended. This is how the process works - when the validity period of medical results expire or are about to expire an IRCC officer will send it for reassessment and the regional medical officer (RMO) at the IRCC Health Branch (HB) will make the determination. Based on this reassessment by the RMO the GCMS file is updated as extended or the applicant is informed to get the medical examination done again. At this time the process for reassessment is not automatic and has to be manually undertaken. Due to the manual nature of this process there can be delays in sending the file for reassessment; updating GCMS with the extension status or informing the applicant (tip - use the web-form and inquire about the status or request your GCMS file). As an applicant you can also get another medical examination done on your own accord (not recommended), in which case submit the upfront sheet to IRCC via the web-form. Other things to keep in mind - if IRCC grants an extension then it will be for no more than 6 months; a re-med on other hand is valid for 1 year. Also, if you see a message on myCIC "
you do not need medical exam" then it quite likely means that your medical results have been sent for reassessment.
Medicals are valid from the date as shown in the GCMS notes and that is the date when medicals were assessed by a Medical officer. Also see this link related to it
Assessing the immigration medical examination
At the final stage IRCC will also check if your medicals and passport are still valid. Before PPR is sent the details of an applicant's COPR, its expiration and the PR visa are input into the GCMS system. The COPR and PR visa cannot be issued by IRCC beyond the validity of the applicants passport or medicals, whichever expires first.