Am I pregnant?

I had my period on December 17-21, my cycle was 31days and the <a href="https://play.google.com/store/apps/details?id=com.glow.android">glow app</a> said I had ovulation calculations December 29-Jan 4. I slept with my boyfriend the 22, 23, 31-Jan 2 and the 4th. On the 6th and 7th I had some light bleeding and I was wondering if this is implantation because I have irregular periods I believe my period isn’t supposed to start till the 17th of Jan. During the 2 days I had mild cramps, hot flashes, and feeling of nausea.