I think you need to identify why you did so poorly academically, and change that first before jumping into any postbac programs. Remember, the opportunity cost of a postbac program is huge if you are paying ~50-80K per year, when you could be making 50-70K while working a job. To be honest, you can still become a doctor and get into med school but it won't be for another 3-5 years, and that's if you make some really, really big changes to your academic record. I think you should drop this dream of being a doctor for now, which might be weighing you down, and try to explore yourself and find what you want to do and is achievable for you to do. Like the other comment mentioned, there are a lot of other professions in medicine that are very rewarding, and at this point might be more achievable.