16 days late.. need advice 😰

Dominique

My last period was on Nov 2,2018. I came off BC in July so I know that August was my withdrawal bleed which made 2 normal periods after... so my period was supposed to come on my bday (dec 20) and I made sure I packed bc so I could skip my period on my bday, but it ended up not showing up. So I had sex on the 22nd and 24th of Dec which was far from my fertile window. Then I noticed I had bleedin the morning of the 25th, and it had clots. But it just ended up being one wipe of it, so I don’t think that would’ve been implantation/ ovulation bleeding that could’ve happened so quickly. It may have been an infection that I picked up and that made me bleed. Now that I’m somewhat late I notice every time I have sex whether it’s before my ovulation window or after my period always delayed . This happened to me before but now I’m scared because when it happened to me the first time I wasn’t active. I’ve spaced out my testing and all done in the morning, and no positives so far.... any advice? Btw the green marks are when I had sex but at the time of expected period my fertile window was in early December. Crossed fingers that I’m not pregnant and it was an Infection or just sex at least that delayed my period.