The Vagus Nerve is kind of a loaded question. It would take a few hours to just plop the basics down on paper.
The Vagus nerve serves to slow the heart down (Parasympathetics innervating the SA node). It also innervates many of the muscles in the throat, so you should have a horse voice and have difficulty swallowing if it has been damaged. While it innervates the GI tract I have read that a damaged Vagus rarely causes severe symptoms in the GI tract. Also the GI tract has its own special nervous system called the Enteric Nervous System (google it!).
Without knowing what else has gone on in your history, there is no way of knowing if it could be your Vagus or not. There are so many things that could be causing this and stuff like smoking, being overweight, nutrition, and family history all play a role.
I hope that you are able to get better. Good luck