Hi Louise. I agree with hypo, an MRI is a test that can just lead to more testing for no reason. MRI's are very good at detecting abnormalities even if they are benign. My sister and I are good examples of this. She has the white lesions you are speaking of and her neurologist said that she probably shouldn't have even known that she had them, because in her case they meant nothing. In my case I had an MRI on my lower back and it showed something on my liver. I was mortified. Well lo and behold it was some cluster of veins that happen in millions of people and mean nothing. He said I should never have know I had this because it is complete benign and will never turn into anything.
I really wouldn't worry. The fact you are better around others speaks volumes. Try working on your anxiety.