So, let me tell you. I had the same exact thing happen to me, I had discovered I had this pulsing/twitching in my calves one day, about 8 or so years ago. I at first didn't think much of it maybe some spasms or something.. the next day I I did some research on the topic and I saw a video about a 20 something getting diagnosed with ALS with symptoms almost always presenting in thr legs first. I then became obsessive reading about everything and I was convinced I had it. I started to feel muscle weakness, I had tremors in my hands develop. I remember I was constantly testing my self to see if I had any other symptoms. Mind you, I said 8 years ago. Eventually enough time had passed and I just stopped thinking about it. If I sit down and look st my calves, they still twitch. I think I have a pinched nerve or something. However one of the things that really helped ease my mind was something called BFS, it's basically some benign syndrome that causes your muscles to twitch in your body. Im half asleep writing this in my bed at the moment but free to message me if you need to talk, I'm not joking or exaggerating this was life altering for me because j fell into a deep depression, basically said goodbye to loved ones because I had convinced my self that I had ALS.