Tapering off meds?

I read that Prozacs and a lot of SSRIs are suppressing REMs. I am on Prozac+Sertraline (now only sertraline because prozac caused excessive sleepiness). However I still have very vivid dreams, and fragmented sleep (which i read are usually due to the REM) so I was thinking if I really need to taper off medication before a test because I figure if its suppressing REM, and I still have REM then it will still show REM. But i read recently that all medication should be wean off before test. So km a bit confused

My situation is a bit unique, because i just had my appointment with my psychiatrist which refer me to the neuro department, i already submit the referral letter but havent gotten any appointment yet. But my next appointment for my psychiatrist is in 2 months and im not sure if ill get the neuro consult in the mean time or not. During the last meeting the psychiatrist did not say anything but previously i did ask and he said medication should not affect sleep study but im kinda doubting, because he did not elaborate at all.

Very scared because idk how tapering off meds will work out for my ocd