Am I Paranoid??

Currently trying to avoid pregnancy, but we hope to start trying in a few months which is why I started charting BBT this month. We used a condom the one day we “did it” in what I think were my fertile days, the rest was unprotected. Had a dip in my BBT yesterday and it went back up today. I’m just scared I miscalculated somehow and I’m pregnant. Hoping you all can help me put my mind at ease