Hi, congrats on quitting. That is totally and completely normal. I couldn't even walk to the bathroom w/o wanting to die. At 6 days you are in the thick of it. Not to scare you, but it takes weeks to start to feel better. Different symptoms ease up at different times. We used for so long, we have to give ourselves time to heal. Hang in there and keep posting.
You're doing GOOD; just hang in there. You will turn a corner in a few days. I'm not saying you will feel 100%, but trust me, it will get better than it is now. You never have to go through this again---just don't give in.
TIPS: Drink water. A lot of it. Try to move...even just a walk to the bathroom and back, or if you can manage it, around the yard. ANY amount of exercise will help you feel better.
Do whatever makes you feel comfortable, and please know you are doing GREAT.