Exercise After Birth

With my first, I was completely out of commission for 8-10 weeks due to a complicated delivery but I surprisingly have a ton of energy after my daughters birth. I am a week postpartum and would like to jump start some exercise. I've been walking a few miles daily. My mom and friends asked if my doctor put any restrictions on working out but she didn't say a word. I don't want to hurt or strain anything. Has anyone started working out? Did your doctor say anything about restrictions? Thanks!