alreadybutnotyet said: "... when the timer goes off, I just reach over and instinctually turn it off and go back to whatever I was working on."

I do this sometimes as well, but in my case (at the present time) the consequences seem to be less severe. You could of course press the snooze button instead of the cancel button.

alreadybutnotyet said: "Shortly thereafter I realize what I've done and now I don't remember if I took my pill or not ..."

A multi-compartment pill container should solve this problem.