I'm sure you've resolved this by now, but I am brand new to this site and have the same TV, and have had the same issue. Sorry it's a bit late.
The pop was definitely the bulb bursting. You can pretty easily do this bulb replacement yourself as Panasonic has provided a nice little pull out module that can be removed by popping the front plate off (which requires no tools at all) and then opening the hatch where the bulb assembly is and loosening just one screw. Once that is done you will be able to slide the entire bulb assembly out of the TV. Though they don't always shatter, I suspect that since you heard it "pop", you will find this assembly full of broken glass.
You can either buy an entire new assembly such as this one...http://www.alltvlamps.com/product_p/ty-la1000.htm
and just slide the new one in,
or if you're comfortable with it, you can open this lamp assembly up by removing just a few more screws (about 4) and just replacing the bulb. I did need to buy a very long #2 Phillips head screw driver to reach one of the screws.
If you search Google for TY-LA1000 you will find both the lamp kit and just the bulb. Be careful though for the really cheap bulbs, it does make a difference, so if it seems drastically cheaper than all the others, there is likely a reason.
Hope this helps you and sorry for the slow response.