Mandy, 56% is not "slightly" positive. If you had that test done at Mayo, they consider anything above 20% to be abnormal. They invented the test, you know. The AChR modulating antibody test is shown as a percentage. A high percentage is seen in many MGers who have a thymoma. Other labs do this "stepping" of the modulating antibodies where a certain percentage is borderline, etc. That is NOT what Mayo does. You can't compare labs and their results.
Good idea not to "ignore" these results.

If you see another neurologist, they may want to retest you to make sure they are both not "false positives." I rather doubt that. If they are retested, it's always good to use the same lab.
Alice is right in that you need to have a neurologist you can trust. But you as a patient need to be your own best advocate, in concert WITH the doctor. If you see too many different neuros, they might start to think you are "doctor s/hopping" to get a diagnosis for something you don't have. Which is utterly ridiculous but that's how some doctors think.
You have a lot going on. You need some help, which we can't give you here! So find those good doctors and get taken care of.
Annie