We kinda already hit on this, but since others will see this posted i wanted to drop a line in hear too.
I've gotten that feeling with both the lipo/ephedrine and e/c stacks. usually its when its taken on an empty stomach and or the dosage is too high. I've even gotten the room spins a few times ... your body will eventually get used to it, but it may be a good idea to back off on the dosage, or eat something with it.
I don't do this for my family, my friends, women, accolades, pride, or ego. I do it for me and no one else, its just part of who I am.