As you recently joined the public sector, you will pay class A PRSI contributions, and you should get a PRSI pension at 65/66, as normal.
Your 12 years of contributions are not lost or dead.
You will also receive an occupational pension from your public sector employer, based on your salary and how many years contributions paid.
The pensions are "integrated" or "co-ordinated", meaning that the 10k annual PRSI pension replaces the first 20k of salary from your job. So your occupational pension is based on the balance of your salary (nett salary).
Nett salary for pension purposes = gross less (2*OACP)