I have no sex drive :(

My hubby and I just welcomed our second baby into the world in July. Before we had our first daughter all we did was have sex! Now it feels like a chore and I ran out of excuses to get me out of doing it a long time ago. Hubby wants it all the time but I just have no desire! The sex is great when I finally talk myself into it. Is there anyway I can get it back? I'm only 22 and I feel like I'm being a 90 year old nun.