8 Weeks PP & still no period!!!!!!

So my baby boy was due July 15th 2018, but made his arrival 3 weeks early on June 25th 2018 @9:36am & is currently 8 weeks & growing fast 😩 He is my 3rd child, i have a girl who will be 6 in a few days & another boy who just turned 3. The reason for this post is because with my 2 other children, i began my pp period after the first month following birth & i have yet to have a period following my latest birth. With my daughter i breast fed (the most) 2 weeks, my 3yr old son (the most) 1 month & with my youngest, i am still currently breastfeeding but only once a day, usually mornings, & the rest of the day formula feeding. I already know when you exclusively bf, it stops your period from returning for a while because it stops ovulation. I'm more or less confused because i stopped exclusively breastfeeding at around 3wks pp & introduced formula & since then have breastfed less & less. I've been breastfeeding him only once a day for about 3wks+ now. So i would've thought i would have a period by now, i have had unprotected sex but I've taken pregnancy test & they have all been negative, i cramp, but still nothing. The first time i had unprotected sex was 16 days ago. I don't know weather, even though I've reduced breastfeeding ALOT, it's because im still feeding only once a day or because i might be pregnant that i havent had my period return. I don't know if I'm testing to early or if I'm just paranoid but wondering if anyone else has had a similar situation???? I wouldn't mind another if i am, they're blessings, just kinda going crazy.... any help?