What Causes Dizziness And Elevated Body Temperature?

Hi, I am wondering if I should be concerned about some symptoms I am having. I went for an hour walk with a friend in the morning a couple of days ago it wasnt real hot, only in the upper 60 s. when we got to our cars we stopped to talk before leaving and I got extremely hot, then I became dizzy, light headed and things started spinning. I had to lean up against my car and lean over to keep myself from getting sick. I thought I was going to faint. It took about 5 imns of sitting in my car with the air conditioning on to feel well enough to drive home. It has been a couple of days and I am still feeling light headed, a little dizzy and slightly nauseous. I also have had heartburn for about a week which is not something I usually experience. Do you think it is a flu bug or should I see my doctor?