K.L.
I experienced the same problem after the birth of my baby - and it really REALLY distanced my husband and I, and we even considered splitting over the issue. But I went to the doctor, told him what was going on - and as it turns out, I was suffering from mild depression. I had given up my career to stay at home with my child, had limited contact with other adults, and was either too stressed, tired, or bitter at my husband for not helping at all around the house. All of those normal, negative feelings just build up and build up, and POOF, the sex drive goes away.
So suck it up, and go to the doctor. Tell him what is going on - I would go to your OB about this as opposed to your general practitioner, as they will be more compassionate and understanding of the issue. My doctor put me on a low dose of the drug Wellbutrin which, unlike many other anti-depressants, has no sexual side effects. With the help of that medication I am much happier, able to deal with stress more appropriately, and actually really feel like having sex again.
Also consider that, also like my husband and I, a fear of getting pregnant again so quickly after the first can also put a damper on the sex drive. I would consider couples counseling: as a psychologist myself, I highly recommend it. It can help in many aspects of your life, and can resolve some of the feelings that lead to a decreased sex drive. It sounds as if your life is very busy and filled with alot of stress - finding time to just be together, and be happily together, can be hard. Take a weekend and go away with your husband, WITHOUT the baby - reconnect as friends and lovers.