First off, I am right there with you with this fear. It started about a month ago for me with some leg stuff. I was sure my leg was weak and it was twitching like crazy, plus it was crampy and felt tight and just weird. In the process of googling about that, I reaquainted myself with Bulbar ALS, and actually thought at the time that it was good I didn't have those symptoms! Fast forward a week, and I've got all those symptoms (although my leg is more or less fine now). So now I am worried I have Bulbar ALS, which is even less likely than the other kind of ALS! I cannot go back to my doctor claiming that I now believe I have Bulbar ALS when he checked my leg out for ALS a month ago, so I am just suffering through, hoping it is not really the case.
With regards to your medication for hair loss, seriously, if you google anything + ALS, you will get a hit about how they are somehow linked (especially on the ALS forums). Seriously. I would encourage you to try it but that is googling and it will ultimately make you feel worse. Like Shawn says, do not, under any circumstances, go on the ALS forum! The people on there are not doctors, and it is impossible to interpret, from a medical stance, what they write. Not only that, but there are hypochondriacs trolling that site daily, and if I were someone who was genuinely ill, dealing with that, I might be tempted to troll back once in a while on there. Seriously. So stay away from there. It is the absolute best thing you can do for yourself.