I know what you mean, DS#2 is going to be 12 weeks soon and I am still figuring out what to do with him (he wakes up to 3 times a night for feed).
Yes, they are constantly changing, but the rate of change does eventually slow down and we can actually 'catch up' and stay ahed in the game....eventually
With growth sprut you also need to up his milk intakes during the day as well, that way he wont catch up at night. If you are topping up with formula after a feed, you need to express then to tell your breasts to make more, which apparently is the purpose of a growth spurt.
Hope that helps.
Now I got to go and figure out what to do with my lil muchikin who wakes every 2hours for feed at night for the pass week (so its not a growth sprut