It looks like way to much water . Do u have holes in the bottom of the cup?let it get sum light it might snap bacc.try not to use a gallon of water for 1 clone.
I grow under a 400 watt bulb.My temp can reach 90 degrees all the time doesnt bother my plants.Try keeping your room cool inorder to make your closet cooler.Depends on what type of plant you have.