16 days still no period.

Nikki
I was on birth control for about four weeks end of Nov. To mid Dec. Bleed the whole month of taking it. On Jan. 9th i had light spotting. Has this happened to anyone and they have been pregnant? I have an appointment saturday to go for a test. This has never happened in all 13 years ive had my period for. I had got pregnant in 2014 after my iud was taken out but however lost the baby. This would be a good thing i believe and i kinda hope i am. Ugh nervous though.