AP, lets take ALS off the table. You are 19...do you know how incredibly rare juvenile ALS is? We are talking about 1 in millions. So, we are only really talking about MS, and this would be a incredibly odd presentation for MS. Your mind is playing tricks on you.
1) Get some professional help with your HA. Trust me it only gets worse if it goes unchecked. You know you have a disease that will decrease your ability to enjoy life and will shorten your life. HA stress will cause you all sorts of issues if you don't do something about it...get some help. Stress is a killer.
2) Only come here...don't google your symptoms...ever under any circumstances. If you need solace...go ask your doc.
3) Get involved in some serious relaxation...whatever that may be for you. Get your mind off this nonsense. Yoga, meditation, prayer...massages...dead sea salt baths...eat right, exercise, get good sleep.