Print out a calendar page for each month and put it near wherever you keep your medicines. Then every time you take something, pencil it in. Make sure you find a template with big enough squares to fit everything into each day.
I ~had~ to do this when I first got sick... or I never would have been able to keep track of meds. For two years I filed it at the end of the month, now it's to the point I don't really need to keep track of so many things.