See you have invested 3 years of your life in order to pursue you dream. Now if you can't afford private college or if you don't want to go for  another year drop, then my honest opinion is to move on.

The primary reason of being a doctor is your dream but you can be serve your nation in many other ways. Go for course such as BSc Biochemistry, Microbiology, Pscyhology, Genetics and pursue a research career in this fields. You will find that your research will be used by doctors in many ways. So thats also an achievement, may be an indirect one but still you will be a part of the clinical systems.

If you do a PhD in Clinical Psychology then you can obviously become an Psychologist which also a kind of Doctor alike profession. Apart from this if you pursue a career in Biology, you can go for Neuroscience, Cognitive Science etc which are fields in which the researches influences the clinical practices.

If you want you can go for BPT and become an Physiotherapist, if you want, you can go for Pharma/Biotechnology and can do research in Vaccicology.

See we all see doctors and as a result it feels like the Doctors are the best. But behind doctors there are a lot of studies and investment of other fields. So if you go for this courses you will be providing knowledges to the doctors for the betterment of the society.

So don't loose hope, Its the time to step up and excel in Life... and I believe if you have perseverance to study for NEET for 3 years, you have a great perseverance limit.

To know more about PCB after 12th, visit the link below:

https://school.careers360.com/articles/courses-after-12th-pcb

I hope this answer helps. All the very best for your future endeavors!