Alot of women who breastfeed usually don't get a period till well after they quit breastfeeding. That's how it was for me and my sister in law also got pregnant while breastfeeding and she didn't have her period. She has 3 kids and it happened with the last two pregnancies.
I got pregnant with my second 6 months later then after him (which was a preterm birth at 27weeks didn't survive ) I got pregnant again at exactly 6 months lol and now I'm 28weeks 3days!
I got pregnant with my second when my daughter was 11 months and never got a period. It took a little over a year to get it back with my second and third, then a few months before getting pregnant again. As you start nursing less over the next couple months your period should return!