Hi Fuzzyhead and welcome to NeuroTalk!
We all have different and varying symptoms with MS. I do understand the cognitive challenges you're having, though. I think that's one of the most difficult "invisible" symptoms we deal with. It's confusing to not only us but those around us, too.
I will tell you that the more stressed out and anxious I got over it the worse it seemed. But, I didn't know how
not to! Fortunately, I've learned to take these peaks and valleys in symptoms in stride and not get too emotionally disrupted about it.
Good luck on your test. Hopefully your nerves will allow you to take the test without too much anxiety.
There are lots of folks here with MS so please continue to come here and read and post. It helps to know you're not alone.