I hear weird thoughts in my head, i can' help it?

don't really know how to describe it but it is taking over my life. for example if i am going to study i hear a thought saying you don't understand, and if i am going to church i hear it saying you hate God and things like that all the time. they are not really audible voices and sounds ,they are just silent thoughts . but all the time they are not what i think bec they oppose all the things i like in my heart , i don't know if i am creating them or what , help me please