Sleep when he sleeps
Oh, it's so hard! but a good rule of thumb is try to sleep
when the baby is sleeping and use others to help out around the house so you can try to catch up on your rest.
It is so important for you to stay as well-rested as possible. Don't feel too frustrated if you feel chronically sleep deprived. It will be a feeling you have for a while, but things will get better with time.