Heavy period, then VERY early light 3 day spotting 7 days after period ended... possibly pregnant?

Hi there, I hope someone can help me...

From November 23-30th, my boyfriend & I had unprotected sex, no pulling out at all, he came inside me multiple times throughout that week, sometimes more than once per day. I think I was possibly ovulating at the time. I then started feeling some mild pregnancy symptoms, but not sure if it was just my mind playing tricks on me. Took 2 pregnancy tests... both negative.

I then got my period a few days late... it was heavy, 6 days, just like my usual ones, but noticed some extra heavy cramping that occurred.

Assuming I wasn't pregnant, I resumed life as usual... then only 7 days after my period ended, I got an unusual light 3 day bleeding, that stopped out of nowhere... no cramps, pains or period symptoms at all, just bleeding. (Red/brownish). Normally, my periods are like clockwork... 28-30 day cycles.

I didn't think anything of it until my mom just told me she & my other female relatives on her side, had all gotten a full regular period during early pregnancy. My question is, could I possibly be experiencing late implantation bleeding? Is it possible for ovulation to occur that long after intercourse?

For more background info: for the past 6 months, I have had endometriosis & endometrial cysts. I was also diagnosed with an arcuate uterus. Could I have possibly miscarried, or conceived late as a result? Please help! I am so nervous & my doctor appointment isn't til January 5th... I also did some holiday drinking & smoking, so I'm really worried about something really bad going on. Thanks & happy holidays <3

[Dr. Kokil Mathur]

Hi!
Yes, your mother is right, at times women do bleed and are still pregnant. I suggest you take a pregnancy test urine pregnancy test is negative then go for a blood pregnancy test. A blood HCG estimation test would be most reliable. If the test is negative then you are not pregnant. If it is borderline, repeat after a week to see if the levels are rising. Rising levels indicate pregnancy. If this too is negative, then your symptoms could be due to endometriosis, hormonal imbalance and PCOD. It would be best to consult a gynecologist.
Take care!