You are sensible to be concenred and there are a very easy ways you can ensure you don't make mistakes with your medication.
* Try wrapping rubber bands around each pill bottle equaling the number of daily doses. Remove one band each time you take the medication, and then replace all of the bands for the following day.
* Keep a medication chart in order to record whether you have taken your pills. This can be a simple dry-erase board on the fridgedoor; put a check next to each medication after you take it.