Sex after a baby

My husband and I have had sex a few times since my little one was born. I’m now 9 weeks pp but I really don’t have interest in sex. At first, it was more because it was uncomfortable but I just have no interest right now. How terrible is this and how do I go about not making my husband feel bad when I turn him down? Is it also terrible that I feel like sex takes too long and I don’t have time for that? If I climb in the bed, I want sleep.