First of all......do not get paranoid!!
I say that with love as I got very paranoid after my diagnosis because my Neuro specifically stated that I had a lesion in the cognitive part of my brain and that concerned her.
With that thought in the back of my head, I started questioning every lapse in thought I had and worried endlessly that I was "losing it".

When I went through a bout of fatigue, my doc put me on Provigil (a Ritalin type drug). It woke me up and put my brain on rapid fire! I mean I was processing info like an IBM computer! So I think that tells me I am okay.....if my cognitive was broke it would have remained broke even on the Provigil....
Now fast forward about 11 years.....I questioned my new Neuro about the lesions in the cognitive part of my brain. His response, "the entire brain is cognitive!...." He knew what I meant but his response made me laugh.

I still walk, talk and can rub my belly and pat my head at the same time. I have days I feel like I have MY M.S. and days I forget I have M.S.......but that is me. For the little things that pop up, I have actually gotten used to them and work around them. I medicate when necessary and go on with life. Unfortunately you are at the scary "what if" part of YOUR process. The longer time goes by you will come to terms with YOUR M.S., and what it stands for in YOUR LIFE. Yes, there will come a day when you even stop telling people you have it. (When I was first diagnosed I told everyone out of sheer shock).
Please hang in there until you get all your answers and know that this is not the end of the world and don't let all the "'well do'ers" tell you horror stories about the John Doe they know that has M.S. and how he is just a head on a pillow.....YIKES. Let that stuff go.
Your job is to stay positive. If you get too freaked out, do what I did and see a councilor. That really helped me put my thoughts together.
Big Hugs Big Hugs Big Hugs