I bought my 94' 22re pickup back in October with 3/4 tank of gas, it has been sitting all winter with the occasional drive. In total I've driven it around 80km (49miles).
so I went for a short drive today and as I was driving (only went about 5km/3miles) the needle ended up going from just under half to the 1/4 line. After 5 minutes of it sitting after I got back, the needle slowly went back to half again.

Could it be just a bad gauge? Maybe the sender in the tank? I'm not sure.

 

You haven't run it long enough to say that there is anything wrong with it at all.

The gauges theory of operation buffers and averages out the tank sender signals. It has to, otherwise, the gauge would be all over the place when the vehicle was in motion.

Calm down and run the truck some more, fill the tank, see what the gauge does, and how it acts as the truck is run a couple hundred miles.

 

Okay thanks I'll do that. My stupid anxiety really gets to my head sometimes.