This is really solid advice, and it's exactly what I did. I flunked my freshman year of college (all C's first semester, all F's second semester) and was dismissed from the university. I got a crappy, soul-draining minimum-wage job in the real world, realized I hate the real world, and now I'm going to a new university. Don't fall into the trap of telling yourself "I'll do better next semester, I'll do better next semester" and waiting for this great epiphany to come. If you're not hacking it, take a step away for a while and evalute what you're doing wrong. I repeat: don't keep telling yourself that you'll do better if it just ain't happening. Do something else for a while and come back to school.
Also, I don't really see why MD would be out of reach. Let's say, hypothetically, that you took a year or two off and prioritized your life. You come back and earn a 4.0 every semester until you graduate. That would be phenomenal, and as far as I'm concerned, would make you a very interesting applicant (obviously, I'm assuming here that you don't bomb the MCAT and that you have decent EC's). Hell, if I was an adcom at Yale, I'd think that was amazing...but, sadly, I'm not an adcom at Yale, so maybe I'm totally off base here.