2001 Ford F-150 Truck has to be jump started

I recently cleaned my battery terminals using NAPA battery terminal cleaner. I now have to jump start my truck every time I attempt to start it. My battery has a full charge, my stereo, lights, alarm, etc. All work and my alternator was replaced within the year. Once the truck is started all is well but there is an burnt egg smell inside. The starter is a little sluggish and clicks when I attempt to start without a jump. Is my starter bad or did I short something like a battery cable?