Procedure of root canal is not always painful. In general, there is usually no pain during the procedure once the local anesthesis is well delivered. Post instrumentation discomfort is well torable if appropriate pain killer is administered.Seeing an endodontist is advised.
I was terrified of having a root canal also, but now having had several, I've learned that you don't feel anything. Sometimes you can have some discomfort afterwards, but nothing major. Did they determine what caused your seizure while getting the anesthetic? This needs to be determined, and if this isn't the same dentist, make sure the new one knows about this. Don't be afraid, I'm sure you'll do just fine.
Make sure that you ask if they are using anything with formaldehyde, most especially sargenti paste. Don't walk away, run if they are. Look up Sargenti Opposition Society for more information. Always ask even if you've been going to that same dentist for decades.
Thanks for all of your helpful tips! I made it through the procedure with no problems so far. I told the endodontist about the seizure (caused supposedly by a lot of the shots at once + adrenaline + panic attack) and he was very patient with me. The shots still hurt, but once they were over I barely felt a thing! I had to ask for more anesthetic a couple of times, but I was in the chair for three hours, so I'm guessing that's why I needed more.
We're happy you did so well!!