LJ mate, I repeat my offer to meet with you and give you some tips.
As to feeling nauseous, what happens is this. Your guts use a lot of blood to digest food. However, muscles also use a lot of blood to move you around and lift weights. So if you lift heavy or go for a run, the body may say, "I can keep the muscles going, or digest food, not both... he's still moving? Okay, I'll get rid of the food then." Thus you feel sick.
In the same way, your brain uses blood, too. So if it all rushes to your legs then there's less for your brain and it starts to shut down - you get tunnel vision, you feel faint, etc.
This gets much less once you have been doing resistance training for a while, and also as you build up your cardiovascular fitness. That's because your body gets better at pumping blood around, so it can supply two things at once.
So you just start slow and build up your strength and fitness, if you feel sick or faint stop and take a breather, then try it a second time - if you're still faint or sick, stop, do a cooldown, stretch and go home.
And don't go looking for videos of accidents on youtube, that really doesn't help you. I mean hey, if I were about to go for a drive in the car would I look at videos of car accidents? It'd make me a nervous wreck, and more likely to crash!
