Previous experience counted after rejoining the central govt hospital job as doctor

Logically, I believe a fresh recruitment would mean a fresh tenure and I am not very confident that the department will take a segregated experience into credit for this particular employment as you resigned the former at your own will. However, feel free to consult the relevant department to ensure the same. More opinions are welcome as well.

The break in service is caused by your own resignation that might have been duly accepted by employer.

The employer might have provided service/relieving certificate for previous tenure of employment and can provide another whenever you separate next time.