If you're feeling nauseous, try sucking on a lemon and/or sniffing peppermint oil on a tissue. This helps me. I don't think it matters too much if you vomit some, I think this is quite common. My very very first attempt, I brought it all up at 2am (liver time) and went for pancakes the next morning in rebellion! Needless to say I didn't succeed that time but by G did I succeed the next time - a flood of toxic bile and stones. No wonder I had't been well for so long!