Quik said:
The burn-out you are feeling now will only get much worse in med school
The exhausted you will be in medical school is definitely of a different animal than the exhausted you are as a premed. Different environment, different challenges. Unless you're planning a career as a professional premed, I wouldn't read too much into the stressfulness of being a premed as a strong predictor of how you'll handle being a med student. For one, you're going through your premed journey more or less alone. In med school, there are many sources of support, from your classmates to the student affairs office to your advisor. My school even has a specific advisor to help those of us who are applying to residency. It's tremendously easier to navigate the system when you have upperclassmen and administrative types who are guiding you through. Also, in med school, you're almost certain to graduate once you start. Like Eik Ooc pointed out, the fact that there is a very real chance that a premed might not get into med school is always gnawing at you in the back of your mind; the only thing worse than delayed gratification is no gratification.
OP, a few things. First, unless you're applying MD/PhD or MD/MS, forget about research. Just cross it off your list altogether. Not necessary to be a competitive candidate for medical school, not worth giving yourself an ulcer over.
Second, how much shadowing have you done already? If you've done enough shadowing where you've gotten to know a physician well enough where s/he can write you a strong LOR, then it's enough. If not, do some more shadowing with that goal in mind. Also keep in mind the fact that if you're applying to DO schools, you will need a letter from a DO at some of them. It's not a bad idea to get a DO letter if you're not sure, because MD schools will also accept them.
Third, if you're feeling like you're hitting a brick wall no matter which way you try to run, maybe you need to stop trying to run. There's no crime in extending your post bac one more year if that's what it takes. I waited an extra year to apply, and it was one of the best decisions I made in terms of preserving my sanity and giving me the time I needed to put together the best possible application of which I was capable.
Finally, give yourself permission to be human. You *are* human. It's ok to get overwhelmed sometimes. It's ok to have doubts about your plans. It's ok to adjust your plans. It's ok to think about being a PA instead of a physician, and it's ok to change your mind and go to PA school instead of medical school if you decide that's what you want to do. It's even ok to decide not to change careers at all if you realize that you miss your old job more than you thought you would. The right decision for you may not be the same as the right decision for other people, and no one who matters will judge you if you decide medicine isn't for you. On the other hand, if you decide that medicine is for you, then you should seriously consider tweaking your plan as I've already said.
Hope this helps, and best of luck.