I had unprotected sex December 5th & 6th, and according to a few period apps I'm about 2 days late - but Friday when my period would be expected I had some blood, enough to just wear one tampon a day and then Saturday and Sunday only a very small amount of bright red blood. I'm not sure if that sounds like spotting or my period, or if that's a sign of pregnancy? So now I've been spotting 3 days. I'm not on birth control, a few days before my period was supposed to come I did start an antibiotic and a probiotic for strep throat. Today I still have light spotting with a little 'clot' I took a pregnancy test this morning which came up negative.

2 days isn't late. Two weeks is late. The antibiotics could have had an effect. I would wait a week and a bit until two weeks have passed and test again. Early testing has a LOT of false negatives.

Good luck!