Hi
It is taking long in your case but it is still O.K.. I have been waiting for 160 days now after medical and according to MP it is still in background check. I think depending on your major at University and your research area it could take longer. However last week the officer asked me for my new passport so I guess they have finished with what they call background check and they need my new passport info to sent the PPR (hopefully).
I just told my story to tell you that your case is fine and the fact that for some people it takes a few days does not mean that you have a problem. The is light at the end of tunnel so just be patient.
I also suggest to follow up with your MP if no news in two weeks. The MP is able to at least check if they have received all the documents and medical and why is it still in process.