Long QT seizures and worry

Hi all. Really long post, I apologize. I'm 20 years old and since I was 3 years old I've had faints/mainly seizures. The first time it happened at 3 I had a temperature. Since then I've had a seizure at least every year, apart from once when I went around 2 years without one.

Since 3 I've had seizures randomly. However have also had one whilst running (twice) one was a seizure one was a faint, when I was on a trampoline, when on a bouncy castle, whilst sat on a bus, whilst sat eating a meal. I also had a seizure once when I was extremely scared and once when I was extremely upset but now they do occur randomly most of the time - I haven't had a seizure for a particular reason in a long time.

Most recently my last seizure was 3 months ago at 4am when I woke up with a leg cramp (wasn't particularly painful or anything, it may have just been coincidence) I got up and walked about then had one.

I have around 5 seconds before I seizure that I know I'm going to have one - then I have a fuzzy feeling in my head and collapse.

My dad passes out vary rarely with pain he cannot tolerate. My auntie used to have seizures/pass out but she grew out of it, whilst my other aunt rarely passes out but has been known to.

I've had:
several ecgs
a holter monitor
an echo
a tilt table test
two mri brain scans

Until recently nothing was found on the tests, they've now seen sinus tachycardia and second degree type 1 heart block on my 4 day holter monitor.

So, after looking online and by chance finding Long QT and worryingly sounding similar to my situation, I'm worried I could have it.

Does anybody have any advice? Does anybody think it sounds like I have it?

I'm currently petrified I'm going to have a sudden cardiac arrest!!

My cardiologist has never mentioned this condition to me. I went to see my GP the other day to talk about Long QT, he said it's highly unlikely I have it as all my ECGs are normal, I said I haven't had a stress test and he said it doesn't matter because when I was in hospital over night recently (hooked upto a monitor) my heart rate randomly started pounding and heart rate went to 177 and he said this would be the equivalent as a stress test as the stress test would just be to increase my heart rate and see what it does at that speed. I didn't have a seizure when I was in the hospital bed and my heart was going 177.

The doctors call me a mystery, but not knowing whats wrong and knowing I could have a seizure at any point is ruining my life.
Thanks.

Hello, after reading up on it it doesn't sound like my condition as I actually collapse and have a seizure and I've had the tilt table test to rule out it but thank you very much.