I know exactly how you feel! I am bloated all the time even though totally gluten-free, so I'm in the process of figuring it out with my doctor. On my really bad days I will be really faint and will start to black out EVERY single time I get up from a chair. When I'm having days like these I also feel a lot of pressure in my head and a horrible headache. Do you have any other symptoms that go along with the bloating and light-headedness?
Sounds like your blood pressure might be low. I've had this many of times. I also have a theory on the dizziness. If there is alot of gas in our stomachs and intestines it must somehow get absorbed in our bloodstream. That has got to be why we feel so spacey and lightheaded. I guess the question would be what is this gas made up of? and can there be anything we can do to rid our bodies of it. Wouldn't it be the opposite of what happens when your deep sea diving and what happens when you get too deep into the waters and get what's called the bends.(sp?)
I guess I should google it and do some researching. Good question though cause I hate that feeling. I wonder if others feel this as much as we do. Doubt if I'll find anything on the subject.