How Can I Raise My Blood Pressure??

I know that this is a really odd question but I found out today that I have very low blood pressure. It has been causing problems for me at work. I stand for long periods of time and have been getting dizzy. I went to the doctor today and my blood pressure is 90/58, which I was told was average for a 5 or 6 year old. She also said that could be what is causing me to get dizzy. So.......any suggestions on healthy ways to raise my blood pressure. Also any information that you have on low blood pressure would be helpful as well. All I can find is stuff on high blood pressure.