I feel really bloated, like i'm going to be sick even though i haven't eaten in over 12 hours. what could be wrong with my digestion?

Not digestion: It is the control mechanisms in the lower brain at fault. There is a 3-way messenger system in the body--brain to body, body to body and body to brain. This requires a lot of cellular energy derived from a healthy god made food diet without all the high calorie "junk" that literally "chokes" cellular engines. These symptoms are affecting millions and nobody is telling them to wise up on diet.