Can very bad anxiety cause GERD symptoms to get worse or act up. I ate food that norm never bothers me had mild anx attack n guts r killin me.

Yes, it is possible. Anxiety has physiological factors with likely chemical changes in the digestive system. During relaxation time, your digestive system relaxes and symptoms are usually relieved.
I've heard that B4. Very bad anxiety seems to be able to make pretty much anything worse - at the very least it 'feels' worse. But gastric symptoms are a frequent complaint. So, it is a good reason to get the anxiety under control. Not only by medication, but by therapy to learn skills. Ways to avoid, reduce and manage anxiety are what you want. Cbt can help. Best!