2002 Ford Truck f 150 wont start

I stopped at the gas station the other day and got gas, then my truck wouldn't start back up... It'll turn over great but just wont catch on.. I replaced the fuel filter and still nothing.. I can hear the fuel pump kick on so I assume thats not it... and the gauges are acting weird.. they will sometimes all go all the way up when the ignition is turned on, then go back.. and the lights will sometimes flash.. Any help would be amazing as I am broke and need my truck for work.. Thanks!
-Brian