I have developed a system to keep track of how I feel on any given day. It is a very simple system, since I am not good at journaling and going into details about, for instance, what I ate the previous day that is causing my symptoms to act up today, or any other detailed research as to my symptoms causes on a daily basis. I have decided to start small-this does not explain why my symptoms are worse on certain days it basically just shows how I feel on that day.
I print out a monthly calendar and I use color coding to determine how I feel on a particular day. I call it my Fibro Scale and it is very vague; Green for a good day, Yellow for a so-so day, and Red for a bad day. It really doesn't tell me much except how many days I was green, yellow or red. For instance in the month of February I had 4.5 Green days, 12.5 Yellow days, and 11 Red days. So far this month I have had 1 Green day, 10 Yellow days, and 6 Red days, and I think I may consider today a Yellow day.
This really doesn't explain much but I think it is good to keep a record of so you can perhaps show your doctor or if you are trying to get disability this may be helpful so that they can see how you feel on a monthly basis.
I hope to move into more detail eventually as to the causes, but for now I like the way this color coding system is working for me, I just wish I could have more Green days.