Hi YOGA
As you can see I moved your post. It was rather lost where it was, so I am hopeful some people can offer you what you need.
I, for one, congratulate you for making the effort to continue the course in the face of hardship and challenges. The reward at the end will be that much greater, I am sure.
Depending on the extent of impact of your medical issues, you can always find areas of investigation where you don't have to do things that are physically too difficult for you. I remember my four years of surveillance, sitting crouched in the back of a van for endless hours. I got out of surveillance and into factuals and this alleviated the physical problems that arose from my surveillance work. There are other options too of course.
Good luck YOGA, never give up, never give up, never give up.
BG