Baby eating too frequently?

Lindsay
My 3 week old is eating 3 ounces of formula every hour and a half to two hours during the day and at night will sleep for 3 1/2 hours or so and will usually eat between 1.5-2.5 ounces. Is she going through a growth spurt? Is she eating too much? I don't know if her weight matters but she's just shy of 9 1/2 pounds.