I can’t get control of my mind

I can’t manage my mind. I’m well versed in how to do it, but I just keep freaking out. I just keep getting totally overwhelmed that I’m feeling feelings like frustration and doubt and I can’t get rid of them. I’m doing an IMMENSE amount of self coaching and belief work and nothing works. I’m trying to allow it but all of my old thoughts still remain that even after allowing it the feelings persist because I haven’t changed the thoughts. I don’t know how to change the thoughts. I feel so stuck here. They just keep screaming in my mind and I can’t escape it.