Hi @redmot that sounds a lot like my condition, POTS (Postural Orthostatic Tachycardic Syndrome). Basically, you stand up, your blood pressure drops, and your heart races to compensate. The test for it is a tilt table. It is not directly connected to diabetes, but it is seen in a fair few diabetics - can I ask if you have any neuropathy, or what your control is like?
The thing is, I'm not sure that it would be diagnosed as that, if that is what it is - I am not a doctor, or any expert, just pointing out the similarities - because a 'normal' blood pressure is 120/80, so yours is about fine, even though you are experiencing symptoms, so they are not going to give you anything to raise it, because hypertension is just as bad.
I think the best thing to do would be to see your doctor.
Hope this helps