It should be in the Download folder... did you do a battery pull: Leave your device on, pull the battery for 20 seconds, put it back in and wait for your device to boot up... did you try that???
Also, did you try to connect your device to your PC and start DM > Application Loader > see if it shows up in that list.
this bug has come up before it happens when you delete a application thats from appworld but not from inside appworld not sure what the fix is as noone ever new