First Unplanned Hospital Visit

I'm coming to you after a restless night, from the purple leather recliner next to my baby's very intimidating, prison-looking crib. We're only here for observation and she is back to normal. Right about 12 hours ago, I glanced over to my 6 week old baby to find her eyes and mouth wide open, face dark red and not breathing. I instantly screamed for my mom and flipped her over to smack her back while mom suctioned out her nose and mouth, and thankfully she finally caught her breath. She was just napping, what could have possibly happened?! My brother called 911 and by the time the ambulance arrived, she was breathing normally and just really upset. She has had a little congestion but apparently she choked on it. I've never been through anything so terrifying in my entire life and can't close my eyes with out seeing my baby girl try to scream for help. How do I get this image out of my head?!