How dehydrated are you? I once wound up in the ER because my blood pressure tanked from dehydration, and I collapsed. In that case, the solution was IV fluids for a couple of days.
I have a problem with dehydration, despite drinking a lot of fluids, and my doctor recommended a sports drink to replace electrolytes. Pedialyte is also good. That helps the other fluids to remain in my system. When I'm feeling the effects of low BP (my signal that I'm dehydrated) a glass of Pedialyte usually provided sufficient electrolytes.