How scary, H.! My daugher had a febrile seizure once when she was 13 months old. We happened to be AT the ped's office at the time, and I totally freaked out because I didn't know what it was. They sent us to the ER because her fever spiked to 104.5!
Once there, they decided to run a million tests to rule out anything else - the did a spinal tap to check for meningitis, they did a CAT scan to check for tumors, then kept her overnight for observation. The next day, they did the EEG to rule out epilepsy - this was BY FAR the least invasive of all the tests they did. They put some jelly-like stuff on the wires and stuck them to her head, then just talked to her while they watched the readout. It didn't bother her at all. Now the spinal tap... that was another story.
It turns out that it was a one-time event in our lives, and I'm sure running all those tests was an overreaction by the docs to be on the safe side. I'm not sorry we did them, though, because it put my mind at ease in case it ever happened again.
Hope that helps, good luck! The good news is they do grow out of them, my doc said by age 5 or 6.
~R.