Very confused

Hey so I’m on the pill (sprintec) and I started my pack that I am about to finish late. I doubled up on the next day and about a week & a half later I had sex with a condom then he finished on me.(Mar 8) Later that night we had sex again for a couple of minutes without a condom but I stopped him because I didnt feel comfortable since we didnt use a condom. About a week before I start my period I get this brown discharge then I start my period and I’ve got the discharge for a week straight like I normally would but I havent started my period. Today (Mar 24) I am 1 day late on my period, is it because I started my pack a day late & doubled up? I took a test and it came out negative so I’m confused I’ve never missed a pill or started a pack late before & im really anxious.