How much to charge to be a nanny?

I will be taking care of a 5 year old little boy starting in a few weeks. I have to go to his house before 5am so his mom can make it to work out of town. I am being paid $150 per week to watch him from 5 am until 4:30 pm monday-Friday and some saturdays. Am I getting ripped off or is that a normal pay?