How do I switch to formula?

Ash

I have been breastfeeding my son for almost exactly one week now and I can't handle it emotionally, I always feel like he's not getting enough to eat and then he sleeps for really long periods in between eating and i have to spend nearly 30 minutes trying to get him to wake up only to have to fight to get him to stay awake while he nurses. So I have to change something, I'm not able to sleep half the time worrying if he's ok or not