It would be helpful if you had a detailed journal here so we could pinpoint exactly what's happening, but based on your description, I can offer some insight. Given the age of your plant (around 2.5 weeks), a balanced 0.5-0.5-0.5 feed seems gentle enough, but even that can be strong for a young seedling, depending on the medium you're using. From your details, I'd guess you've possibly overfed or overwatered—both of which are very easy to do early on. At this stage, seedlings are sensitive, and a little goes a long way.
Additionally, keep an eye on your lighting. Seedlings don’t need intense light, and the symptoms you're seeing could indicate some stress from too high an intensity. The plant might be trying to shield itself, leading to weird leaf shapes and general stress. I'd suggest backing the light off a bit or reducing its intensity until the plant stabilizes.
Also, double-check your humidity levels. Seedlings prefer higher humidity (60-70% - no higher than 70%), and low humidity can easily stress them out.
Right now, the key is to simplify things: reduce feeding frequency, dial back lighting, adjust humidity if needed, and avoid additional stress like training until the plant shows signs of recovery.