Greetings, Ruckinge. Welcome to the Straight Dope. I hope the reference to “Dope” in the title isn’t the only thing which brought you to these sunny shores. 
If you are looking for either legal or medical advice, you’re probably not going to get it on the Boards.
That being the case, I would suspect that this is more a matter of opinion than settled fact, which means that this will probably end up in “IMHO” (In My Humble Opinion).
If you’re going to do drugs, or hang around with people who are doing drugs, the possibility of getting in trouble is part of the deal. Period. You can get in a boatload more trouble for leaving someone to die than you are likely to get for calling for help.
If the kind of trouble you refer to is “Trouble with Mom and Dad” rather than “Trouble with John Law,” (a possibility which your reference to Middle School health eduction brings to mind), may I suggest that you are way too young to be screwing around with drugs? If you can’t wrap your head around the fact that you may have to deal with an O.D. and take whatever consequences which develop, you should not be putting yourself into this situation.
The “Oh, #$%^!” option (run like hell and never look back) is a lousy idea. First of all, if you don’t care about the people you are with enough to at least call an ambulance from a pay phone before you get out of Dodge, you probably need either new friends or a new soul, and you certainly need a new hobby. At the very least, you should consider why you are using drugs around people who you don’t care about, and who, presumably, don’t care about you, either. If your relationship with these people is so superficial that your fear of authorities outweighs fear for their lives, you should be damned careful, because the acquaintances you are with might well take off and leave YOU to die if YOU happen to be the one who O.D.s. If, on the other hand, you yourself don’t actually TAKE drugs, your presence among people who do leaves you in the unenviable position of “automatic designated driver.” In any event, you are responsible. Period. It stinks, but there it is.
Call an ambulance. Particularly if you are screwed up yourself, do NOT drive the person to the hospital. Assuming that they have no reason to believe that their own personal safety is at risk, the ambulance drivers will be interested in keeping your friend alive, not in whatever illegal stuff you may be up to (other than wanting to know exactly what drugs your friend took.)
FWIW, when I drove a friend to the hospital in similar circumstances the only thing the nurses wanted to know was who she was, what she took and (in case I happened to know) what insurance she had. I probably should have called the ambulance instead, but she lived only about a mile or so from the hospital, and she did not appear to be in imminent danger of death. (I don’t doubt that she could have easily ended up dead if left to her own resources. I know this girl very well.)