What’s going on?

So my last period began on 11/5/17 and I started my new pack of birth control after like I usually do, however I missed about 5 pills because I had forgotten to take them and it caused me to start bleeding on 11/21/17. Everything seemed normal and I started a new pack of pills when the period was over. About 2 days after that I noticed I was spotting bright pink and sometimes brown discharge. This only happened on and off for about 3 days and I was cramping without any blood flow. I did have unprotected sex during the time of missing those pills. Is it possible that I could be pregnant and when would I be able to test and know if I was pregnant or not?