Missing period

Bluu

My period is 5 days late and my boyfriend and I had sex more than a month ago. I got my period after me and him had sex and I had my period on time. We haven’t had sex ever since but for some reason my period is 5 days late now. My periods are always on time and every 31 days I always get it but I’m missing my period this time. Also I gave birth to a beautiful baby girl 7 months ago, not sure it that may have to do anything with it.