One day late for period

I am one day late for my period. I've been having mild cramping, lower back pain, tender breasts and feel nausea to the point I feel I'm going to vomit. My partner and I had protected sex three times since my last period, and twice unprotected just before my expected period date, which hasn't happen yet. Could I be pregnant? I am usually regular, every 28 days which usually lasts 6 days and my last period was three days early. Am I overthinking it?