Was it a blue dye test? They are known to give false positives. I've gotten a couple when I wasn't pregnant. Also, in the morning becuase you slept all night w/out peeing your pee is less diluted and so its more common to come up positive on a test since your hcg is more present hence why they say test in the morning with first morning urine. If you've been drinking water and peeing often today you could have diluted your pee. I'd either go to the store and get a pink dye test and hold my pee for a couple hours... or wait until the morning and test again using a pink dye/digital test.