I have been where you are. I was convinced I had MS and the doctors were missing something. I had all the symptoms, the tingling, the numbness, the tremors/twitches, you name it. Doctors told me I did not have it, but rather I had severe anxiety that was causing my body to go haywire. The physical symptoms of anxiety can often mimic MS. They really can, anyone on this forum will tell you that. And it can last for a LONG time, especially if you keep perpetuating the cycle of anxiety by reading up on diseases and feeding into your health anxiety. That's the problem right there. The doctors who are confirming you DO NOT have MS won't help to ease your fears because they aren't treating your underlying cause- anxiety. They can tell you that you do not have MS till they are blue in the face and it will not help you because your anxiety will always suppress your reasoning. That is what health anxiety does. It is beyond reasoning. Therefore, it is best to treat your anxiety, and your "MS symptoms" will begin to fade. Mine did, and so did it for several other anxiety suffers. Therapy and medication will work wonders, I could not believe what a difference it made! I have random twitching still, but the doc said it was BFS, or benign fasciculation syndrome, brought on by...wait for it...SEVERE ANXIETY! It will not hurt me, tons of people have it. Your muscles just twitch randomly and it is for literally no reason.
Worst case scenario, you will receive an MS diagnosis. But, YOU WON'T receive one because you don't have it. For the sake of this post, let's say you do. MS is a very livable disease. Medical technology has come a long way and many people live normal lives with MS. My grandpa had it and he lived to be well into his 80's. He died form something completely unrelated. I met several people from his MS support group, who were older, and they were ALL FINE. You couldn't even tell they had MS. So, my point is- YOU DON'T HAVE MS. But, if you did, you would still be fine. I know you already know this, but living in a state of constant anxiety and worry is no way to live at all. Medication, therapy, a number of things can help you like it helped me. There are people who actually have MS that are living full, happy lives. Then, there are those who do not have MS who are miserable because they are obsessing over a disease they more than likely do not have.
You can get through this. YOU ARE FINE.