I don't know what tests they did. but some tests are not very sensitive, and may be normal even with significant respiratory muscle weakness, if you have good lungs.

In order to fully assess your respiratory muscles you need to have a few tests- MIP, MEP, and MVV as a minimum. And those have to be done more then once.

I doubt that your respiratory symptoms are only due to anxiety, and I would put it very low on the list, until proper respiratory evaluation is done.

symptoms like breathing and swallowing are treated more seriously, because they can potentially endanger your life. other symptoms even if more bothersome, can be treated less emergent.

a mild degree of respiratory muscle weakness does not endanger your life, but most neurologists don't know how to assess respiratory symptoms or their severity.

you will learn with time, how to assess the severity of your own symptoms. when it is enough to just rest some more, and when more significant actions are required.

I think it is also a good idea to have a good pulmonologist ( preferably one with a good understanding of neuromuscular diseases) involved in your care.
He/she will be able to evaluate if you have any significant respiratory muscle weakness, and can also help you learn how to monitor it yourself.