Due to the length of the symptom, the doctor moved you into the probable MS category. For me, my first recollection was foot-drop. I have been as long as six months unable to walk, too. It is important to realize that it is not our physique that defines us as a person.
Even now, it has been over a year since my left leg started dragging along. My service dog pulls me across campus as I escort my son to college each day. I drive with hand controls. Dwelling upon the inability to move an appendage only leads to worry and stress which can cause further problems.
The lesions can interrupt the electrical message from your head to your legs, but the connection, in your case, has been re-established because the damaged insulation has scarred over. The connection will never be as good as the original nerve insulation, but you can still enjoy life.
On days when your legs do not work, try the pool. I was powerlifting for many years with MS. I took the necessary steps to stay safe. If you are running, keep running, but keep in mind that you need to watch your exhaustion which can leave you with problems for recovery. You might consider getting a partner to run with you. I was out running with my Marine Corps platoon when my right arm stopped working and my legs stopped in 1982. That was my last serious run. Nowadays I am content to have my service dog walk me as fast as I can go, but there are days when the distance between classroom buildings seems too far. On those days I slow down.
It is hard to give up the "rush" you get from a brisk workout. I have a passive Exercycle too. I get a "rush" but not like I had when powerlifting. Still, I do not dwell on what I could do; I dwell on what I am able to do.
It is important to avoid falling into a "pity-party" where you are the only guest. On days when I just cannot do anything, I do nothing but rest. I try to assign goals to obtain. I make sure the bar is low enough to reach on bad days and then as I get better, I raise the bar.
Are your running days over? Hardly, in my opinion. Running does not define you. Though I do not know you, I dare say that it is your heart and mind that define you. My body does not work and has not worked like I want, but I am still a Dad and husband. Do not corner yourself into having your appendages define you.
I am keeping you in my prayers.