Hi There, Last Month, My Period Came Three Days Earlier

Hi there, last month, my period came three days earlier . That was on the 16th of September. I had my first ever sex on the 24th of that month. There was protection. I had another protected sex a week later that was on the 3rd of October. My menses was to start on the 16th of this month but it hasn't come yet. It's two days late. I have had the signs like pimples n breasts tenderness but the blood hasn't started flowing.. Please what may be wrong?