My little girl had a seizure today

My dog Maggie had a seizure today. This is the first time she has ever done this, that I know of. She is a 3 yo Golden Lab.....we have had her since she was 6 months. I was very surprised and terrified watching her go through this seizure today. It must have lasted for at least 2 minutes, which doesn't really sound like a long time, but it felt like eternity. We recently changed her food to one that was prescribed by the vet.....the vet thinks she has a food allergy so she is on something called Hill's prescription diet Canine Z/D ultra allergen-free. Does anyone think that the food change could have caused the seizure or am I just panicking? I am calling my vet in the morning.

Thanks,

Mendy