One of the things I did to keep some kind of sanity was to dedicate a series of notebooks to my treatment and healing process. On each notebook's cover I'd write the time spanned within. Anything to help me stay organized.
I used the notebook to take any and all notes before, during and after medical appointments, and if I happened to write a note on some other piece of paper, I'd tape it on the appropriate page to keep everything together....
...I'd also use it to track the cornucopia of medications you end up taking when going through chemo and after surgery... each one has its own lifecycle, so I'd end up creating a list with open checkboxes that I'd fill in once each drug was taken.
This was very handy when trying to stick to the prescribed schedule for certain drugs: I learned the very hard way that if you stuck to the schedule you could gain more power over a given side effect, and when that side effect is intense pain or nausea you definitely want to do everything you can to maximize the "helper" meds. Tracking the meds was also helpful when I needed to talk with my MDs and/or Nurses about side effects: I'd be able to give them the info they needed to help me.
Another thing the notebook was great for was tracking phone calls, messages and conversations with my medical team. If I had a question about a side effect between two chemo cycles, I'd write it down, call the Doc's office and if I had to leave a voicemail, I'd note it in my notebook. Then, when they called back I'd know why they were calling me! (If you've gone through chemo, you've probably had at least one or two episodes of "chemo brain," yes?!)
I would also write notes to myself as I did in one of the pictures I attached -- "Feeling NAUSEOUS! ... I was not eating anything throughout the chemo. NEXT TIME MUST snack throughout!" This helped me learn from my mistakes and improve my experience as best as possible.
Finally, as I write this, I'm glad I did this and kept the notebooks, as I'm able to refer to them and share some tips with anyone whom (I think it's "whom," not "who"!) this might help.