pregnant again in the 6 weeks postpartum

Emotional post- please be nice.
Has anyone found them selves pregnant again straight after having their baby. I found out I'm 4 weeks pregnant and my baby is 9 weeks old. Big shock! I won't go into the full story but we have come to terms with the shock. However I'm now very worried about the pregnancy. I hardly feel pregnant really. Has anyone been in the same situation, what was your pregnancy like and was everything ok? Thanks x