2009 Titan won't start

I have a 2009 Nissan Titan, was running fine. Today I went to start it and it just "clicked", I checked the battery connection, turned on the headlights and dome light all good. Tried to start it again and it started right up. I put it in drive and it would only accelerate to idle speed, the gas pedal had no effect and the service engine light and the SLIP light both came on. I parked it, turned it off and disconnected the battery, after reconnecting the battery it turns over but won't start. Any help or direction is greatly appreciated.

Thanks, Eric