As salam alaikum ustadh I prayed a prayer in the mosque that's a biddah because my father in law was pushing me to a little. So i just did it because i didn't wanna embarrass myself, is this apostasy and do I need to ask him to renew my nikah? I regret what I've done.

Ustadh AbdulAziz al-Haqqan

It is allowed to pray behind the people of innovation, but better pray behind the people of Sunnah. But you suffer from waswas and you really need to seek out a trustworthy Muslim doctor.