What do you think is wrong?

Yesterday I had a really bad headache and my neck and back were stiff and sore. Late last night my temperature reached 103.4. I took some ibuprofen and piled on the blankets. I woke up this morning feeling much better. My temperature was normal. I went to the mall with my friend and we were standing in line when I started feeling sick. I left the line to sit down but then everything was getting dark and I was wobbling. I walked into a girl and then everything went black and my legs gave out. I ped out. The mall medic came and talked to me and then I got up and left, and I feel fine now. What could it be?