I'm 17 and have had Neurocardiogenic Syncope since I was eight -- at least, that was the first time I had a presyncopic episode. I've fainted completely (collapsed) five times over the past few years, but I get presyncope pretty much every time I stand up, which is annoying, because I have to keep getting down on the floor (sigh).
With me it is the blood pressure, though, which I guess is less dangerous since there is warning. But I get a lot of symptoms in between episodes -- dizziness, shaking, feeling very cold, chest/abdominal pain, aching legs, and extreme fatigue which is exacerbated by exercise. Fun, eh?
I'm on Zoloft (for social anxiety and panic disorder) but I'm not sure it's made it any better. However, my cardiologist did say she was glad I was on it, because it should help. Mostly there's nothing I can do except drink a lot of water, get lots of sodium, and be careful.
Anyway, my case sounds pretty different from yours, but I guess my point is ... I've had this thing for a long time, and it hasn't killed me yet.
You'll probably be just fine; work with your doctors, try what you can, and make do. Trust me, this is a LOT less scary than cancer! Sure it's your heart, but it is most always a manageable illness.