Fast breathing and seizures

A few days ago my elderly rough collie had a big tonic-clonic seizure. We went to the vet, blood work showed a possible infection (se we have antibiotics) but no temperature and her heart rate was okay.

Before the seizure she got into bed with me and was consistently breathing really fast, over 60 a minute. Not the occasional panting and back to normal. I haven't noticed this before, but of course am now watching everything super closely. The weather is really hot and humid and when I look at the other dogs they are also breathing fast, though not as fast as her. Don't have A/C, but am staying home with ice infront of a fan and have moved my bed downstairs to try to keep her relaxed and cool. Am also giving her occasional dips in a tepid bath (only leg high so as not to shock or upset her as she isn't a fan of water).

Is the fast breathing part of epilepsy? Or is the fast breathing bringing seizures on? She had one possible one in the evening, then the big one in the early hours. The vet gave us rescue meds in case it happens again. If it does we need to bring her back for anti-epilepsy meds.

She is 11. The big one is the first we have seen, but she is always very wobbly around noise so may have had others that were situational and we didn't realise.