I'M LOST AT WHAT TO THINK HELP!

So here lately my 3 year old daughter has been coming to me telling me she wants a baby sister. Mom is having her a baby sister not daddy (were split up thought maybe he got someone else pregnant.) I been talking to for 6 months (Were not ready for a relationship he just got out of one of 5 years and I did with my kids dad of 4 years) were real close he was there for me threw everything known him 6 years he was my freshman homecoming date. Well before my daughter said anything I said had a surprise for him but I was scared and afraid to disappoint him and him not like it (was something I bought him) well he got confused and he's like are you pregnant. Well few says later I got up to get food and for no reason because I didn't know what I wanted i start crying my brothers like oh shes pregnant. My daughter told me again last night in having her a baby sister. I'm suppose to start my period tomorrow or Sunday sometimes mine are a day or ask off. Well I been blowing everyone is saying no and now I'm like am i? (I just had my son may 10th and I breastfeed and he had never came in me) Is it possibly my daughter is trying to tell me something? I'm just over thinking right?