I can say with relative certainty that the sleep dep most definitely had a hand in the hallucinations and quite possibly the dry heaves. The heaves could have been caused by the fasting though, since my mind has played plenty of different tricks on me to try and get me to consume something. From headaches, to drymouth, to stomach pains, you name it. You're right though starting small is a good way to get used to it, though I am from the school of jumping into cold water instead of working myself in. Different strokes, right? Are you sure it's your body that needs the convincing and not your mind? What leads you to conclude it's your body?