afraid of being a mother of 2

Br
My baby boy was planned and as time is getting closer and closer I'm starting to get nervous about having 2 kids I went from not wanting any kids to having one kid and not wanting anymore, to wanting a 2nd kid to complete my family. But lately I've been wandering what if I don't have enough patience for 2 kids, what if I show too much attention to one and not enough to the other, what if I lose my mind because it's way too much. Lol any advice ladies?