Hannah also had a growth spurt recently, but it lasted 2 WEEKS!! Now she's much better and back to 3 bottles a day at creche (plus breast the rest of the time and cereal and supper).
Give your baby what he needs. The tin recommendations are for average babies, maybe your son is just growing a bit quicker or a bit hungrier than other babies!!!
As for cramps, both my girls suffered from immature digestive tracts and cried each and every time they poo'd or farted until about 6 - 8 weeks old. It was not colic, this was confirmed by the paed. It was a bit better with Hannah, but Mia really suffered and screamed such painful cries when she poo'd I literally used to cry with her!! We found that Bennet's Colic Mixture helped with those cramps.
@Eve, I work full day plus studied when Mia was a baby and now with Hannah, in fact I'm finishing up my last exam on Tuesday (hopefully if I pass). It is hard, I'm not going to lie to you. You need a good support system, hubby to help babysit while you have to do assignments, study, etc. But it is achievable. I found personally, that three subjects per semester was the absolute maximum and that was pushing it to total stress levels at assignment and exam deadlines, but I've managed so far and as I say, I write my final exam on Tuesday.
Good luck