BakedPotatoSoup

Your GRE scores are honestly solid, even for the higher tier programs. Also, many students admitted into a doctoral psychology program don't have any publications under their belt, so you don't have to worry much there. The main concern would be addressing your overall undergrad GPA, which isn't as bad as you perceive - it's still in the 3.0 range, and your major GPAs of 3.7 each are good.
I also had a similar background as you during undergrad; I was also a pre-medicine student who switched to psychology late into his college career. Talking with other psychology graduate students, this happens more than you'd realize - many of them were also former pre-med students. In my personal statements for doctoral Clinical Psychology program applications, I directly addressed my poor grades in pre-medicine coursework by explaining my lack of passion for those areas, and I described my journey of discovering psychology as my true calling. This seems to be the approach you should consider taking as well; I don't think a post-bacc or Master's program is necessary.

Instead of a post-bacc or Master's program, I'd suggest applying for paid RA positions in social psychology labs - preferably in a study similar to your area of research. Admissions committees for graduate psychology programs are strongly attracted to applicants with significant research experience in their area of interest. And if you manage to work for a private investigator who's well-connected with other Social Psychology professors in the field, you'd have won the jackpot ;-) 
In any case, this is some advice that helped me land an acceptance into my top-choice doctoral Clinical Psychology program  The road ahead may be difficult, but keep focused on your goals and don't be afraid to ask questions. I wish you the best!