I Am 80 Yrs Old .For The Last 3 Weeks

I am 80 yrs old .For the last 3 weeks I have had a nauseous feeling in the stomach as soon as iI start walking around upon rising in te morning. i usually have fruit and protein drink for breakfast ( nutriblast) but now cannot bear the idea. after 2 hours te sensation disappears but my appetite does not fullreturn till about midday. I have no systemic diseases and BP is excellent and Iexercise 3xweek dancing 2xweek gym.