Gas Gauge Needle Dipping More Quickly Than it Should?

After 1 1/2 years or so in a CPO 2020 CX-5 Touring Edition I just began to notice that the gas gauge is decreasing/depleting in small increments (like 1/16th or 1/32nd ) after only driving approximately 8-10 miles at a time. (Suburban/local driving such as errands , drs appts, etc.). AM I IMAGINING THIS? Has anyone experienced similar, where the gas mileage is inordinately poor or there could be a leak (though I don't see gasoline on the pavement where I park the car)? Wow, a 5 year old car like this shouldn't be having mechanical problems yet as far as I'm concerned ;(

I'm so upset and now obsessing about it and staring at the gauge while driving in dread. I was told by the dealership they'd likely charge me $250 JUST to diagnose the problem if it's not under warranty as I approach a Service appt next week. I'm guessing they'll tell me that's not under warranty for a CPO purchased 9/29/23. I can't afford that and g-d only knows the cost to fix whatever problem it is! Are local mechanics who may not charge to diagnose it capable of figuring this out and fixing it in 'newer' cars like this that rely on a lot of high tech sensors and such?

I can't tell if the needle moving this quickly was always the case and I just never noticed it, but this car took me on a 5-6 hour drive a year ago with maybe only one gas refill each way. I'm terrible at figuring out mileage but I did fill and reset the trip meter to 0 and am taking photos of the odometer each time I notice it dip, with the # of miles included in the photo at each increment. I'm just below (I think) 1/8th of a tank having filled it about a week ago. I don't work nor drive a ton sooooooo.

Any thoughts, suggestions to help me determine if or what's the problem at no or nominal cost? (I hate to sound cheap but I'm on an extremely limited budget and may regret buying this car that already guzzles gas, but can't afford to lose money selling it or trading it in at this time.)