Feeling cold is normal, don't worry about it. I've done about 20 juice fasts, and most times I get a little cold. I don't mean to sound flip, but just wear a sweater or something extra. It always passes for me. Hang in there.
V-8? Ughhh! No!! LOL. The stuff is chock full of salt and other dead juices.
I often juice my entire amount in the morning, to last thru the day. Plus it is good to add distilled water to cut or thin your juice to make it last longer. 100% is okay too. Be careful of juicing too much fruits.