I have been working with a patent lawyer who drafted my Idea into a patent and filed the patent. The patent went through a normal process of patenting such as search, reviewing by the examiner and finally it was granted (it is EU patent). In all stages, the patent lawyer was helping me and gave me advices to keep my claims and patents and answered the question of examiners. The whole process took me around 4 years and in each step I paid my lawyer.
One year after the time which my patent is granted, I accidentally came up with an older patent (EU and US) which is very similar to my patent idea and it actually claims the same claims as my patent. It is very strange for me why this patent has not been discovered during patent search. Since this patent is 5 years older than mine, it actually can invalidate my patent.
I am wondering if I can sue my patent lawyer for not doing his job well. I appreciate if you guys can give me some clue.