What Causes Dizziness And Nausea?

I m 47, female, and healthy. I am not on medication and eat pretty healthily. I have been experiencing a light headed and almost floating feeling lately, at different times of the day. It usually happens when I m driving and now has started happening when I m at home doing little to nothing in particular and the frequency has increased as well. Used to be once a week or less, now about weekly. A feeling of nausea follows and it seems like a panic attack...only I m not stressed at all and am wondering if it s my heart. I ve had no chest pain or arm pain and haven t noticed an irregular heartbeat at all. Going to the doc tomorrow and want to make sure to know all the possiblities I can before talking with him. Thank you.