1 day late

My app says I’m a day late, and it’s always been accurate in previous months. I took an Up and Up test from Target and my husband says it’s negative but I thought I saw a VERY faint line. I didn’t take a plan b so that’s not a reason for my period being late. I would say little to no stress so I can’t see that being a factor.

I’m very confused as to why I’m not getting my period? And no signs of it coming. Has anyone else tried this specific test?