Many new mothers know exactly what you're going through. Nowadays, more than half of all mothers with infants work. And even more mothers with older babies and children are working. You can read stories shared by mothers who have been there at http://www.womenshealth.gov/pregnancy/childbirth-beyond/returning-to-work/. Their advice and lessons learned can help you through the transition.
This answer is based on source information from the National Women's Health Information Center.