Could I be pregnant?

Patient: I had sex a few days during my fertile window in November around the week of the 17th. I had somewhat of a cycle the beginning of December but it wasn’t heavy as usual. My period for this month is now 5 days late. I’m never late. Could I be pregnant? My breast are sore and tender, which is usual for me.

Symptoms: My breast are sore and tender. I feel nauseated sometimes.