Did I hallucinate or not?

I was walking across my lawn 5 minutes ago and all the sudden I see this big ball of sparks explode 5 feet away. I ran into my house and told my parnets and my dad came out with a flashlight and saw nothing... do you think I hallucinated the big ball of sparks?? I am kindof tiered because I didn't fall asleep till around midnight last night but I am really wondering what casued this. It may have been real but I have no clue and all the signs point to it not being real. Also... what are some diseases that cause hallucinations and what is the liklyhood I have them?? I am a HUGE hypochondriac so I am freaking out right now:p