I may have fallen asleep in sujood but wasn’t sure until my mother told me. I continued praying because I thought sleep in that position did not break wudu. Later I realized I should repeat the prayer. Is not stopping immediately considered making light of Allah’s rulings or kufr?

Ustadh AbdulAziz al-Haqqan

No, these are compulsive thoughts (waswas) that you need to stay away from. Close the door on it altogether and ignore.