revoke after the decree???

oh yes I think that's what I am doing...just waiting for something to happen....The bio dad is a *&*&^%$^&(*&^%%R%&&&&,,,,,lol and made our life a living hell....and now I just can't accept that we are free from it and I'm honestly having anxiety attacks from thinking of it....For 5 years this man terrorized us with his threats and being free, finally is just too unreal for me...I keep thinking..."he will find a way "...it will never end.....but... I have read that for 6 months after you receive your final decree, the bio parents can change their mind....but if that's true...then why have the 7 days after they sign TPR to change their mind? I'm in NC...does anyone know this for sure? I mean why give them 2 chances to change their minds....???