MS question 38yo male

I'm a 38 year old male and in the last eight months I have lost all the muscle between the thumb and index finger on both hands evenly, my thumbs are so weak I am not able to button my pants or shirts without great effort. I have also developed small twitches in my arms(upper and lower), my legs(upper and lower), as well as stomach. Slight occasional cramping in my calves and toes. My MRI was negative for MS but could I still possibly have it or, ALS, or something similar? Thank you for your time!