What's the deal with soda pop?

Lately whenever I buy a can of pop it is flat. What is the deal with this. The first time I thought maybe it was a one time thing, you know like maybe someone got lazy at the pop factory and forgot to put bubbles in it. But it's happened like 4 times in the past week. The first time was when I got an orange crush with my pizza. The pizza was ok but when I opened the pop it didn't make that "Fsshhh" sound, it just made this really empty "clunk" sound. I thought "No big deal, so the pops flat, so what. I like orange juice, this is just a can of orange juice now". But then it happened again and again and I wondered if I would ever have a fizzy pop again. Now whenever I am about to drink a pop I get nervous. Will it let me down again?