What Causes Nausea, Hot Flashes, Sweating And Disorientation?

I had a nausea feeling and felt hot and sweaty while I was working, and then felt a little dizzy as I walked to to sit down and felt a little disoriented. I continued to feel nausea, and went outside to sit and continued to feel about the same for about an hour. I then came back in the house and started to feel cold and chilled and wrapped up in a blanket after 1/2 hour I decided to have a snack, felt a little better, and after another half hour no longer felt nausea, but still felt some equilibrium problem which slowly went away as I rested the remainder of the day. I am 70 years old and have had good health. Any thoughts on what it may have been?