What Causes Dizzy Spells While Lying On Stomach?

Hi, I am 25 years old. For several years I've had this problem where I could not lay on my stomach. I would get severe dizzy spells and the room will start spinning. After getting up, the dizziness eventually goes away. No matter if Im on a mattress or on the floor it always happens. I also tend to get short of breath and sick to my stomach when this happens. I am confused on why I keep getting these spells. According to the doctor my blood pressure is fine with each check up. Can you tell me what maybe going on?