help Please

So i had twins on 6/18. breastfeeding and formula feeding. i had what i *think* was my period on October 10-13. I say think because it was pretty light, definitely not what I was expecting, and it was only for 3 days. so I was supposed to get my period today...well I didn't. my husband and I had been having unprotected sex since my 6 week post partum check up. since I thought I got my period back, he started pulling out. BUT what are the chances I ovulated and got pregnant and that was actually implantation bleeding??? 🤔🙈🙈🙈