Help please regarding daughter's seizure.

Our daughter (12 years old, type 1 for 5 years) had a seizure on Sunday at 730 am. It was the most horrific experience of our lives and we are both still reeling from it. Full convulsions, jerking, grunting. She was completely gone for 15 minutes. First thing we thought was a hypo, but I tested her and she was 8.0. Hospital kept her in overnight, all bloods came back clear. She's absolutely fine in herself now, can't remember a thing. An hour before bed, she was extremely high (25). Keytones were fine. She had 4 units novorapid as correction, should have brought her down to 10,which is fine for going to bed. Surely she couldn't have crashed at 730 the following morning that severely?! Does anyone have any thoughts or help? The last thing we want is another seizure, it broke our hearts to see her like that. X