Hey Gem,
Sorry, I'm just seeing this thread for the first time. I hope you get better soon. There's lots of good advice already in this thread that I cannot improve upon- especially from Tora Ziyal, BillJ, and Kestra.
However, a very important thing to note here is something I've seen examples time and time again is that the patient can decide their own prognosis. If you're convinced this is going to get the better of you- then it will. If you decide you're stronger than this neurological disorder (and you are) you will persevere and even thrive after you've beaten this.
Keep a positive attitude. If you find positivity here, then by all means stick around. But, if your first Docotr's opinion turns out to be correct, and if your really have only six months to live- then I wouldn't waste my time online. I get out of the house and experience life while you still are able.
If you'll permit me, I have a story to share. Back in 2003, my dad had a cough. Yes, just a cough. It was Father's Day and my sister and I made him go get it checked out. He was admitted to the hospital the following week. He passed away on July 1st at the age of 64 from Stage IV lung cancer just over two weeks later. I only share this to illustrate the fact that we never know how long we have. You're young, get out and enjoy life.
I do have to stand with the others that point out that if your boyfriend or whatever he is can't support especially now, then you drop him and trade up. Find someone who can and will support you and be there for you when you need them. You're smart, beautiful, and have great tastes in Sci-fi fandom. You can do better.