Ok, first talk to your doctor. I was on 50mg for 2 1/2 years and then 100mg for 6 mo. The feeling you are having are common. Check out the Pristiq withdrawal discussion board. You are not alone!!! I am now no longer on Pristiq and took my final pill 4 weeks ago. I started feeling happy about life again about 2 weeks ago. Yes you will have withdrawal symptoms and brain zaps. The brain zaps are your neurotransmitters firing in your brain and you can hear them and feel them. I stopped the medication because even I started noticing that something had really changed in me after my doctor upped my dosage. I was having hyperhidrosis (heavy sweating). It took me 3 weeks to taper off but now I am getting my groove back. I felt like you, no drive for anything. Emotionally I felt flat and I knew it was not good. You must taper off Pristiq as it changes your brain chemistry and you have to give it time to get back to normal. Do not go cold turkey because of the bad symptoms you can have. When you read the other discussion board you will see how others have tapered off. I love my doctor, but these medications are not for long term use and should be monitored better. You do not want Seratonin Syndrome which can be caused from long term use of this classification type drug. My doc wanted me to taper for only a week, but that really scared me so I came up with my own after reading what others had done. Check out this link to read about this drug and then talk to your doctor about getting off of it. http://en.wikipedia.org/wiki/Serotonin-norepinephrine_reuptake_inhibitor
Good luck to you and let me know how you are!