soil looks pretty wet, are you waiting for it to dry out a bit before watering again? this soil has amendments in it right? this first days you shouldn't need any nutrients feed tho, i've seen much worse seedlings recover so, you will have to be a little patient.
Patience is a virtue, and one that I don't have! You were right though and they have started to grow fast now that they have recovered. It must have been the transparent cups that slowed their growth because they started to grow once I covered them up. The only thing I have added to my soil is worm castings.