Sounds to me like a blood pressure issue.You should visit your doctor and have him/her check your blood pressure/heart rate in 3 positions...laying flat, then sitting, and lastly, standing. (this test is called Orthostatics, BTW)
Hi and sorry you have this. It could be the hypotension mentioned above since its when you stand up. It could also be benign paroxysmal positional vertigo. It usually lasts about a minute and feels like the room is spinning or like you are going to fall over. It can be caused by an ear infection or pressure on the ear. You need to get someone to drive you in as you might get it while driving. They have some simple tests for you to do by tilting your head and then seeing if it comes on at that time and so forth. If it is an ear infection they may give you an antibiotic and have you take pseudofed. If it is caused by something else they can help instruct you how to get over this. See your doctor as soon as you can.
mkh9
Postural hypotension-consult your doc.