Something for the rag and bone man...
No soldier outlives a thousand chances. But every soldier believes in Chance and trusts his luck.
I know it may sound tedious, but I'd recommend checking out the card list here on BGG's file section and comparing it to your current cards.
You may find that you're missing some or quite a few. It's possible that you ended up with a duplicate blister pack of cards and/or are missing one entirely.
So compare your cards to the list, and if you are having an error and not just having misplaced them somewhere (like accidentally shuffling them into a deck other than weapons) etc, you can contact Paizo. They've been real good to people with missing cards out of the box.
I agree with this recommendation. I checked what I have against the file and found out that I have quite a few cards missing.