It's possible that a seedling that young wasn't too stoked about being transplanted. Even large healthy plants take some time to recover from transplant shock. My guess is that it's trying to adapt. That's a lot of trauma for a new sprout bro. Can't say for sure that that's the only problem, but its definitely a part of it. I have no idea how hot it is in your room, the humidity and if you've been watering correctly.