Is it normal to have a drowning sensation when you bend over and your head is in the upside down position? it came on quick. no joke.

Yes: When you turn upside down, your abdominal contents push against your thorax or chest making it harder to breath and inflate your lungs. The tongue can fall to obstruct breathing, the blood return by gravity alone can increase and the heart and the thorax has to accommodate that.

May need eval: This may be vertigo, a sense of spatial disorientation created when the position sensors in your inner ear are disoriented. Changes in position can sometimes bring this out. If it persists or increases you should discuss it with your doc.