I won't say I know how you feel because, IMO, no one does. I will say you need to see a doctor. Venticular tachycardia can be treated as can unstable angina. In my case, it's a simple old fashioned drug - not one of the fancy new ones. I have at least two more heart problems. It was thought I'd not live to grow up. PM me if you want the name of the med so you can ask your doctor about it. The pain you're having does sound like angina. BTW, I beat you - 240 beats a minute if I exercise with my hands over my head. You don't circulate much blood at that rate.
Please see your doctor. You can't do otherwise for your son's sake. And if not for yourself, then for us. I haven't been here long, but it's clear to me that you are the glue that holds this thread together.
This is a depressing time of the year. Between gray skies and the the approaching holidays, it can be an unhappy time. If your finances permit, a sunlamp is wonderful.
On a happier note, my weight is under one of those numbers with a 0 on the end. First time in 13 months. Woohoo!