Definitely get a thorough check up that includes oxygen levels. Are there certain times when the dizziness is worse or is it like that all of the time? I also think of the medication that we use, some of them can affect the balance mechanism of our inner ears, causing dizziness. Especially the aminoglycosides such as Tobramycin, gentamycin, vancomycin etc....I can tell you from personal experience that it can be quite profound...I was on gentamycin IV a year ago, 2 weeks in, I could not get out of bed without falling the dizziness was so bad. I looked like a drunken sailor when I walked, I felt like I was on a ship on rough seas. If you are on any of these meds, it could be the issue as well.
Either way, sounds like you need the doc to take a look at you and possibly run some tests on you.
Jenn 40 w/CF