Weird hallucinations? I'm not sure.

Hello, I'm an 18 year old male and I'm a freshman in college. For about the past week I would be walking through campus and I see a florescent blue circle in a random location, It is not on my eye because I can look around and its in the same spot. I see it anywhere from 1-3 times a day and I'm starting to get worried, Is this a common thing or not I have no idea.

Thanks