Advice/ opinion?

I recently downloaded another <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">period apps</a> Bc I can’t rely on this one for the reason that most of the time I’m either 3 or 4 days late or one or two more days all the time for AF (also to mention I’m sexually active) So I downloaded the other one to see which one calculates it closer to AF but now one says I’m 11 days late and the other one 13 days late. I spotted/lightly bled for like half a day (the 13th of this month) which would of been after the last day of the app that says 13 days late, but after that nothing to this day, so I’m wondering is there a chance i can possibly be pregnant? Also the first day of my last period was December 4th. I know the easiest way to rule out options is to do a pregnancy test, but I currently don’t have free time to go buy one, I’m busy during the day and my only free time is late at night but no stores are open. But for now till I can get one , what’s your opinion?