In the cab gas tank problem!

[The Swed]

Drove the truck to work for the first time (6/1/2016) and showed the truck to a few coworkers at noon and all was fine. I noticed the cap was not fully seated so I pulled the rubber up on the gas cap and gave it a good turn. At 6pm on a hot day I go out to the truck and the smell of was so strong! Open all the windows and drove home higher then a kite. Pulled the seat forward that night to find the floor board with a thin layer of gas on both sides and the 3M spray glue was now jelly and the insulation wasn't attached to the floor anymore. I cleaned off gas and glue off the floor with soap and water and it still smells strong. Drove it to work today (6/2/2016) and released the gas cap and heard it suck and the gas tank pop/oil can so much for the cap venting!? I believe the high out side temps, almost full tank and the gas cap tightly in place pushed the gas passed the float fuel level sending unit rubber gasket. I'm attaching photos. BTW I did clean out the tank, red coat the tank and replaced the float a month ago. Any thoughts on how to fix this? Wrong cap? Bad cap?

Thanks