what the hecks wrong with my eye??

okay so this is something completly weird… on new years eve everything was fine right? okay ima explain what I did that day I woke up at 8 went to the dentist I got my cavity fixed and yes they numbed me up.. (but this was the RIGHT side of my face/mouth) and then I wasnt feeling good so I slept on the couch for a couple of hours..I got up ate some food on my otherside of my mouth and then we hung out wit the fam waiting for new years..after that got done (I went to bed a bit after 1) I woke up the next day and I didnt realize till hours later when my mom pointed it out that I woke up with a purplish redish eye…well it was that color around my eye area..beleive it or not it looked like someone had PUNCHED me in the eye..but this was my left side of my face…so I doubt that the numbing had to do anything with it.. but I am completly confused and speechless! I don’t know how I got it! I swear I didnt drink, I didnt get in a fight, I didnt hit my face/eye are or anything so why the h3ll do I have a bruised eye?! it seriously looks like someone punched me in the face..but it doesnt look completly purple its more reddish and rough feeling…like a bruise when its healing…but still..wtf?! someone have any idea of why the cause??? and the next day of having it it hurt whenever I would squint or move much of my left eye..which sucked..but that didnt last more than a day though..