Two things during my cancer journey that helped me keep track of everything from diagnosis/treatment options to my medications or pain meds was one I recorded every appointment with every person I was in contact with.

One, I bought a Philips VoiceTracer DVT1160 ($42 on Amazon) to record providers so I could always go back and play so nothing is missed.

Second, for meds I used this attached pdf to keep track.

Hope this helps ease some of the frustration.