Oh, poor guy! Trapdoor snails are livebearers, but should only breed once or twice a year. So it's unlikely, but possible that way! Apples lay eggs, so that option is out.
This is a good website to see if you ended up with some other type of snail:
Snail Species List .:. Freshwater Aquarium Snail Species Information Pages
Unfortunately, otocinclus probably can't survive in your tank
They're super delicate. They require pristine water and aquatic plants, and shouldn't be kept in tanks under twenty gallons :/