I would recommend consulting your physician ASAP. I am not sure if this is a cardiovascular issue or an abnormal lab, i.e. anemia.
As Londres stated, a visit to a physician is indicated.
Dehydration and/or anemia (low hematocrit) is the probable etiology, as Londres pointed out, but an in-person evaluation is required. There are other possibilities, including various blood disorders that compromise the ability of the cells to transport oxygen to the tissues. The high heart rate is compensatory to maintain a unit volume of oxygenated blood to pass through the carotid sensors.
The nausea and paleness suggests you have approached the limit of compensation, and are experiencing severe oxygen deficiency. Unresolved that could lead to death of cardiac tissue. In other words, a life-threatening situation.
I want you to place a physician's visit at the very head of your list of "things to do".
Ask them to take orthostatic blood pressures, which reflect the level of dehydration.
Do not stop until you have a definitive answer to your problem.
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I currently have this problem, when my blood pressure drops too low my heartrate goes into the 170-180 range. When your blood pressure drops your heartrate will increase in order to bring your pressure back to normal. You can wear compression/support hose to keep your pressure more regulated. You should also see a dr. to rule out any cardiac problems. Good luck
Thank you for answering my question!! I am going to make an apt asap