If you are going to look after your new baby, then you need to look after yourself as well. If you are breast feeding, then you have to make sure you are eating the right diet and getting enough rest while you are producing breast milk. It can be easy at this time to focus exclusively on the baby and forget that you need taking care of too, so give yourself a few minutes if you can each day, to think about what you are going to eat and when you can have a rest.
Small babies tend to sleep fairly randomly through the day and night, so you could wear yourself out if you try to keep going all day and stay awake at night looking after your baby. Give yourself permission to rest during the day while your baby is asleep, the phone calls, housework and other tasks you were thinking of can wait for a time while you recharge your batteries. Better to aim to do only one or two things a day and pace yourself, rather than try to carry on at the speed you were used to before, and ending up exhausting yourself.
It can be difficult to eat proper meals as well, so see if you can get organised some easy to prepare healthy meals, such as pasta and salads, eggs or soup. Staying healthy will help you to have the energy to keep going.