Jesus, man! I hope some good luck comes your way.
Medical school, eh? Well, I definitely think you have the brains for it–you’re one hell of a smart dude.
I don’t know if you have the patience for it though.
Let me pass onto you a few lessons that life has taught me: no one is free of hardship in this life, and there is no path through it that is easy. I’ve been through university, got myself two degrees, and the stress was almost unbearable. To get through school–especially med school–you reeeaaally have to dig your nose into the books… but what else you gonna do in life? If all is hardship, you might as well go through some kinda hardship that stands a chance of paying off in the long run, right?
The point in life is not to find some easy road that soothes you like a mother coddling a baby, but to choose your preferred hardship–and that’s not to be interpreted as the least painful hardship, but the hardship that is the most meaningful to you, the hardship that you can stand behind and say: this is worth it. It’s like the hardship of enduring a sickness versus the hardship of working out at the gym–no one chooses to be sick, no one wants that, so to endure sickness is often unbearable, but to work out at the gym, the break a sweat, to feel the burn, is quite bearable. Not because it hurts less, but because we want it–we want it because of what it means to us: that we are achieving something, we are getting somewhere with it, becoming stronger, becoming faster, becoming better–it means something to us so much deeper than being sick and throwing up means to us.
On a side note, it’s interesting to me that you want to become an embalmer as opposed to the many other occupations you could choose. If you’re such a monster, you could have been a soldier, firing bullets at the enemy; you could have joined the mafia, become a gangster, and cut people’s fingers off to satisfy some twisted, sadistic pleasure; you could have become a worker in a slaughtering house, torturing animals for fun (Turd Ferguson tells me you used to work in a meat packing plant–why did you quit?). To be an embalmer tells me that you are interested in death and the macabre, but not in torture or the suffering of others–the dead are already dead–embalming them does not bring about any further suffering or torture–in fact, you would be helping others with the grieving process of the loss of a loved one, helping them to bring closure (maybe even guiding a soul in their migratory journey into the afterlife if you believe in that sort of thing).
In other words, I don’t think you’re as much of a demon as you make yourself out to be–you like the macabre, the gothic, but I don’t think you’re a monster. You live in the darkness, but you’re not a bad soul. I think what you express is your own pain, not an evil spirit.
I seem to recall once you told us about your suffering from chronic pain. There is a part of the brain called the anterior cingulate gyrus which is involved in both physical and emotional pain, and I suspect yours is overactive. This could account for your innate inner demon–neurologically wired to suffer.
Drugs might help–maybe–but the effect of drugs, especially pain killers and antidepressants usually wear off; what you need is a lifestyle that least stimulates the anterior cingulate gyrus, some set of circumstances in your life that gives your ACG the least reasons to jump up and down and signal warnings that life sucks.
Good luck! 
(seriously! I don’t know how the hell you’re gonna do that).
All I can say is, if you get a grant to go to college and study medicine, study your fucking ass off! Like I say, I don’t know if you have the patience to do it, but if you’re gonna do something that you abhor (which is a given in life), might as well make it something that stands of chance of paying off in the long run.