Rule 1: Take a Breath
Lets take an example of how an adcom might evaluate you.
1) Academic: GPA is inconsistent. Even with family issues, there is no clear trend that I can say if your are a 3.5 student or a 3.9 student? Either one could be a function of course load, luck, or a sprint in academic work. Being a from a Top 20 will be at best a minor boost. Major doesnt matter directly, but in your case it may hurt your indirectly by the courses you have taken. The adcom will see a series of less than impressive grades in the many science courses you have taken, particularly those in many ways, are most related to medical school.
2) Graduate: Most graduate GPAs do not help overcome a weak undergrad GPA, especially an MPH. While completing an MPH can be considered an accomplishment, in your case in may actually work against you. Before the growth Postbacc and SMPs, MPH was used by many applicants as an attempt to overcome a weak GPA. The trend was noticed by many adcoms and thus weakened the overall impact of MPH programs. So while completing an MPH will be seen as an accomplishment, unless it is accompanied by other evidence showing motivation and commitment in public health, it may be seen as nothing more than an attempt to mask a weak uGPA
(http://forums.studentdoctor.net/threads/graduate-gpa-and-med-school.1202050/#post-17783513)
3) Your MCAT is average or below at many places. Consider it a pass
4) Healthcare Experience: You have 500+ hours shadowing (which is doing something for yourself) and 100 hours hospital volunteering (which is doing something for others). These ratios are backwards. Maybe 50, 100 perhaps 200 hours shadowing (as in physician observation) is more than enough to have exposure. More than that appears to many adcoms as simply ego for the applicant's own gratification, especially when compared to no mention of community/volunteer service, experience with underserved populations, or leadership experience.
5) Your PS will not have much noticeable impact from the weight of all the above
6) I would speculate here that some of your "superb" LORs are from the doctors you have shadowed . Since so many applicants get shadowing experience letters, of which the vast majority highly recommending the applicant with little weight or evidence behind the recommendations, many adcoms view these letters as much less importance than other academic evaluations. The theory of LOR/LOE is evaluate a student's academic abilities and characteristics; not what they did as much as what is behind how they did so, what characteristics. While some schools do require them, shadowing letters tend to come in behind academic LOR, PI/Research, Volunteer/Service/Leadership and Character.
Most schools evaluate and prioritize application in broad tranche or "piles" along the lines "Superior" "Outstanding" "Excellent" "Above Average" "Average" "Below Average" "Mediocre " "Reject" (depends on the school but 5 to 7 piles). Most schools wont ever get into the average or below average tranches without some other important factors such as URM, Peace Corps, Military Vet, Outstanding ECs, and noteworthy research publication
At a moderate school you are below average to mediocre at best. At reach schools you might make mediocre, but I doubt it. Since schools trim several thousand applications to a several hundred interview slots to a 100 or so matriculants, your chances at MD with the current record are quite low.
What to do? You need GPA repair pure and simple. A year of advance work in a DIY postbacc or an SMP would be in order.
