Hello there,
May i ask why do you have a shunt?
Hydrocephalus? hemmorage? cyst?
I have a friend, who like you, was born very prematurely, she is fitted with a shunt due to hemmorage and hydrocephalus. She is weakened on her left side of her body due to this is where the bleed was on her brain when she was born.
She suffers from headaches alot and finds it very difficult concentrating in school, this fustrates her highly.

How long have you had headaches every day for?
&& when was your last revision?

Sorry about all the questions, this might just help into whats going on =)

Im 17 too, i have an large arachnoid cyst and hydrocephalus and i have a VA shunt fitted, as of 8 days ago. Before then i had a VP shunt. I suffer from headaches alot, but luckily not EVERY day.
When i have my headaches, i tend to just take paracetemol every 4 hours along with ibuprofen every 6 hours. There are times where no medicine even touches these headaches but then of course theres times when this resolves them.
Ive miss so much time form school too.
In september just gone, i was one day away from beginning the first day of college, my shunt had been working fine for 12 years until upto that day when i had an routine checkup and intercranial pressure was found. A DAY BEFORE COLLEGE BEGAN!! so since then ive been in and out of hospital, for operations, corrective operations, procedures, tests, appointments, post ops check ups etc, and then when im not in hospital i have bad days, shunt pains, stomach pain (before the VA shunt) since september i have had 4 acedemic subjects cut down to just one now, which takes up and hour and half 3 times a week, i will be lucky to get there twice a week, but all in all i am attending college about 30% of the time, if that. Its a pain isnt it!!

Yeh so theres my story, just for you to compare and adjust =)