Pills and period

So I usually start my period on Sunday and end it Friday nights. Well Saturday, Sunday and today (Monday) I have had a little discharge and I don't know if it's my period ending, or it's it's the spotting you get when you're pregnant. I take my pill within an hour each day and we use condoms. This is the first time I have had discharge over the date and I know it's almost impossible for me to be pregnant, but thoughts?