Did I have sun poisoning or a heat stroke?

I got sun burned yesterday on my chest. No blisters but very red. Today I was a the beach in 95 degree heat eating hot food at a table with no shade. I stood to get a bottle of water and became so dizzy I couldnt stand. I sat back down and asked a friend to bring me a bottle. I felt nauseous so I got up to stand in line for the restroom, leaning against the wall in the shade. My vision blurred and the dizziness increased. Everything began to look like photo negatives. I felt like I was about to fall and faint so I forced myself to walk back to the table and sit. As I did my vision worsened and everything began to blur worse and then everything turned bright white and I couldnt make out any shapes. I finally got water and it helped slightly. I walked down to the water to cool off with the help of friends so I didn't fall. My vision returned slowly but the dizziness, shaking and nausea didn't go away. What happened? Oh, and Im 25 and otherwise healthy, with a family history of stoke.