I was with people in the mosque who were performing a prayer that is an innovation and someone told me to do it as well, im ashamed to say in the heat of the moment I prayed because I didn't wanna embarrass myself since everyone else was praying it, am i a disbeliever Because i didn't believe in it?

Ustadh AbdulAziz al-Haqqan

It is wrong and not allowed to do so, but you are not a disbeliever, this is OCD and waswas, dismiss them.