Is Pregnancy Possible While On Birth Control Pills?

Hi doc, I’m taking althea just after my period ends, because my husband arrives without notice. I am done taking the 21 pills and now on my free pill period. I am worried because my husband did not know I’m on pill, and we are active even during my free pill period, is there a possibility that I might conceive? I can feel my breast starting to get tender after taking a pack of Althea … please you can also send a reply to my email YYYY@YYYY