Help!

So back in December I had sex during my ovulation period. I took plan b after realizing it was during my ovulation week because we didn’t use protection. I’m not on BC to women in my family (myself included) had bad experiences. I’ve had three periods (first one was in December, then one in January and one in February) but this month I’m almost two weeks away from having a missed period. My life has been stressful. I did have my second born last June and stopped breast feeding around 4 months due to my supply just completely vanished. Could I be pregnant or is it that my body isn’t back on track completely yet. If someone who’s had this experience before happen to them? Did your period finally come? If not did it come the next month? Any advice would be greatly appreciated.