How do working mums cope with 2 or more children without helper?

Hi, I'm currently 17 weeks pregnant and my first born just turned 2 years old. Wondering how does mommies cope with 2 children without any helper? Plus going back to work after maternity end.. My husband work irregular hours. He won't be able to help much. I'm worried if I don't get a helper I can't cope with caring a newborn and a toddler.. any tips please?