What is your setup like? Are there any other inhabitants, runny poop could mean worms, but you need to take the gecko to the vet to get a fecal sample and medication.
I would have to agree with Bell, take it to the vet and get a fecal exam done, as for the sleeping all day, they are nocturnal so thats not really any worry, and sometimes leos just go off feeders, ive had geckos be fine on mealies as hatchlings but then refusing to eat them as they have matured.
First step just take it to the vet to have a check done. Make sure you have got the right hides and temperature in your viv.