Chills and extreme weakness?

I'm a 15 year old boy and last night when I went to bed, I had extreme chills. I was shivering and shaking and a lot of goose bumps. It's the exact same feeling when you have a flu but when I checked my temperature, it was normal. And when I woke up to eat breakfast, it was gone. But suddenly My legs started shaking and I felt extreme weakness like I was about to pass out the weakness was so bad I thought I was going to die. So I went back to bed for about two hours and then when I woke up it was like I was never sick! What could have this been? Please help? :( I'm scared