Don't worry, completely normal. My DD is nearly 20 weeks and we still haven't DTD. Sometimes I feel like it, but most of the time I just want to sleep or rest/chill out. My DH & I still cuddle etc.... but it goes no further. I think for me also is that I don't feel that attractive atm b/c of my flabby tum etc... Once I start to feel better about myself I am sure my libido will return to 'normal'.
I would take your time, you don't want to feel obligated or like it is a chore, you then may feel resenting dtd.