Is it normal not to have libido after birth?

Yes. You are going through major emotional and physical changes and healing. Your hormones levels are much different than you are used too and it is very normal to experience many different emotions. Highs, lows, interest or lack of interest in sex. As your body returns to its prepregnancy state you will begin to feel like yourself again. If you are concerned talk with your doctor.
Yes. Your internal hormones are changing every day. Now they are helping you to take care of your infant. Make sure your and your spouse continue to make time away from your child to reconnect. Soon the libido will return!