A few concerns on TTC the fourth time around

I'm in my mid-20s married with three kids. My husband and I want a big family so we're trying again. I just had a baby last year and I stopped breastfeeding him two months ago my period came back right after but it's been late two months in a row now. I was supposed to start my period today I've been experiencing mild cramping but no blood. I tried Preseed this month as well. I took a hpt today and it was negative. I'm just concerned with whats going on with my body. I am a little bit worried though we haven't been trying long. Any advice and shared experiences please and thank you!