Bodywide twitching, muscle fatigability please help!

[Danni1337]

Hello I am 18 years old high school student and for last year I am going through hell and no one knows what is wrong. It all started after flu. My body just became very weak, every movement was hard and I literally felt weakness everywhere. This resolved after like a week but shortly after that I started to experience twitching in my legs which then spread everywhere else in body and has never gone away since that. Next symptom I noticed was muscle weakness or muscle fatigability. Simply my muscles become very weak after minor exertion and I have to rest. So I am basically done with sports. I was in a hospital 2 times and everything was fine. I had 2 MRIs, blood tests, and basically everything had good results except EMG. It showed some polyphasic potentials and some myogenic lesion but I just dont know what does it mean none of those words and my neuro did not have time to explain it. In the end I ended up with this diagnosis: Benign fasciculation syndrome, anxiety disorder and some stress disorder. But I have few questions about that. I am currently very anxious because I fear some serious diseases because I have almost all symptoms like some type of dystrophy, ALS or any other serious neuromuscular disease. So my questions:
1. Can you have dirty EMG with Benign fasciculation syndrome?
2. Is it possible to have these symptoms with BFS or anxiety disorder?
3. What does "polyphasic potentials" and "myogenic lesion" in EMG terms mean?
4. If not BFS to which serious neuromuscular disease are my symptoms the closest?
Thank you for your time