Hang in there... and call your doctor tell them what is going on. I called after a week of headaches and this is what they said to me!
"Didn't we tell you that if you got really hungry you could have something high protien/low fat?"
Of course I was HELL NO! you did not mention anything of the sort!
They should be able to give you options, maybe you can try a different protien shake or add something to it.
I bought one of those small bullet blenders and add ice and fruit, it comes out real thick and makes me feel like I am having a icecream shake.