Ease my late period woes, 2XC! [20F]

I really appreciate any insight about what might be going on. Throwaway account, if that matters at all. 20 years old.

Here are the facts, 2XC:

1. I last had my period starting around November 25 and going until around November 30th.

2. I have been sexually inactive for months until December 20th, when my boyfriend visited me. We had sex on the 20th and basically once every day until the 27th. We used the condom, it did not break or tear, and pretty much our only possible concern is that a MINISCULE bit of pre-come may have grazed the side of the condom during application.

3. My period is fairly regular, even though I don't keep track of it from month to month it typically appears when I expect it. It is usually fairly heavy and lasts about 5 days.

4. Before my boyfriend visited (maybe 1 or 2 days before) I had about one evening of bleeding (spotting?) Put on a pad, it was essentially gone the next day. Could this have been my period in a very brief form?

5. All this has been making me stress. Not in an extremely anxious way but in a constant state of worry. Is that really enough to delay a period? I've read posts about periods up to 72 days late. I plan on taking a pregnancy test in the morning but I don't even know if it's soon enough yet.

I CAN'T STOP THINKING ABOUT THIS :( Any words of encouragement or advice will be greatly appreciated!