It's tiring hun, isn't it! Trish's thread should give you the information you are looking for. Unfortunately there is a lot of mis-information around, and it's just not true that growth spurts have a time limit. Sometimes they might only last for a couple of days, but they can last for weeks. Babies do a lot of growing and developing a short space of time, so it makes sense that they need lots of milk to fuel it.

I hope it passes soon for you.