Teeth Moved-Braces Removed 5 Days Ago?

I had my braces removed on a Monday. The orthodontist gave me a removable retainer and a bonded retainer was placed on the back of my front top & bottom teeth. Friday I noticed a new open space where I previously had the biggest gap. I've been wearing my removable retainer every night. My gums were also puffy when they took the braces off and they don't seem to be getting any better-they hurt when I put the retainer in at night. What is the problem??