One common cause of a low blood pressure with high pulse rate is dehydration
. The thing is a person needs to know what is your heart rate? What is your BP? In nursing you do a test checking your BP lying down, sitting, and then standing up....a variation of 15 or more points would indicate you are dehydrated. You can get a head rush from getting up too quickly if you are hypotensive (low blood pressure). Sweets aren't going to affect your blood pressure. Try increasing your fluid intake, have something like Gatorade rain for the electrolytes and then see how you feel. Regarding stress
....you would be amazed at the symptoms a person can have from these conditions, all you have to do is research to see.