Yet another little issue/question...

[81GMCSierra1500]

Hey again all,

I've been noticing another issue with my truck that's been showing up lately, I can't get an accurate fuel level reading, it'll go from full, to empty, to a quarter, to 3/4 then back to full in under a minute, and it repeats this cycle in random fashion every 10 minutes or so, is it just the fuel sloshing around in the tank, or do I have an issue?