You may be suffering from a condition called BPV, Benign Positional Vertigo. People with this often have dizziness when in bed and getting up, because of the movements that occur when in this position. I have a link for you to look at, see down below in the link for symptoms. Here is the link
When asked about their dizziness, patients with benign positional vertigo (BPV) characteristically describe that the room or world is spinning. However, other descriptions, such as rocking, tilting, somersaulting, and the like, are also possible. All that matters is that an illusion of motion is caused by a misperception of a stimulus (the otoliths). Diagnosis of BPV is based on a characteristic history and a positive Hallpike test.