At what point do I consider euthanasia for my epileptic dog?

We got my dog back in June she is 4 years old, and she was having seizures but unfortunately the vet misdiagnosed them. They started becoming more frequent in August. We’ve spent $4000+ in the span of a month and a half ruling out tumors, liver shunts, etc. they diagnosed her with idiopathic epilepsy. She began her kepra, they upped her dose and she seemed great for a few days but they unfortunately became frequent again, they said it was a honeymoon phase. They then began her on phenobarbital with a loading dose and IV over night. She lasted 12 days without a seizure -we were hopeful but unfortunately had one that last 3 minutes again, then another the next day for 3 minutes. She has a drs appointment on Friday to check her liver levels, but at what point do I decide it is time. My husband and I discussed we will not go to the extent of starting a third medication. When she’s not seizing she’s most of the time happy, but also does become very shaky for hours, or tired. My biggest fear is that her clusters will begin again and lead to one where she doesn’t come out of one. I don’t want a seizure to be her last moments for her as well as my husband and I. I quit my job to work from home so that I could give her her meds (x 4 a day). We’ve spent tons of money even with her having insurance. This just has been mentally draining but I don’t want to euthanize her too early because of my selfish reasons, but I also don’t want her to be miserable.

Below is a list of her recorded seizures-

Seizure 9/25 Started medication-9/26 Seizure- 9/26 Seizure 9/28 Seizure 9/30 Seizure 9/30 Seizure 10/3 Seizure 10/4 Gave 1.5mL 3PM- vomited at 4PM Gave .5mL at 12AM Gave .5mL at 8AM Diarrhea at 10:30 AM Vomited bile twice at 1PM Seizure at 8:37 PM (lasted 3 minutes) Seizure 10/6 lasted 10 seconds Seizure 10/7 seemed to convulse a little Seizure 10/13, 1 1/2 minute @8:30pm Seizure 10/14 3 1/2 minutes @7:40 pm Seizure 10/15 30 seconds @1PM Seizure 10/15 4 minutes @4:22 PM Seizure 10/15 3 minutes @8:02 PM Seizure 10/16 3 minutes @6PM Seizure 10/16 3 minutes @8:20 PM Seizure 10/17 4 minutes @3:52PM Seizure 10/17 2 minutes @4:35 PM Seizure possibly @ 7 PM Seizure 10/17 4 minutes @7:23PM Loading pheno dose 10/17 Seizure 10/18 30 seconds @4PM Started pheno 10/18 1mL 9PM Seizure 10/18 30 seconds @9:15PM Seizure 10/18 3 minutes @11:40PM Seizure 10/31 3 minutes @7:50PM Seizure 11/1 3 minutes @8:33PM