For the past month I have had nothing but runny stools, and in the past 2 weeks I can't keep any food down longer than 10 minutes.
I feel light headed and really weak.
Your diarrhea has
continued for a month, making it more chronic and persistent rather than
acute. The possible causes are long, but
chronic infection is a concern, especially if you've recently traveled out of
the US. Other diagnoses to consider are chronic
pancreatitis, celiac disease, lactose intolerance, and possibly even stomach or
intestinal cancer, to name a few. Try to
pay attention to any recent changes in your eating habits or if you've started
taking a new medication recently. Be
very careful not to let yourself get dehydrated and go see your doctor ASAP.
I am not sure your symptoms are related to acid reflux, but you can check all of your symptoms here in the symptoms database. You can also take an assessment here to determine if the vomiting is something associated with the acid reflux.
There are also some shareposts here written by people who had problems with vomiting.
Hope this helps somewhat. You should really see your doctor if this continues because only your doctor can determine what is best for you. Online sites are great for finding information that will help you ask all the important questions of your doctor, but they shouldn't take the place of your doctor's advice.
Take care and stay in touch. Let us know how you are doing!