I really feel for you, becuase i am going through the same, as you, my 18 year old daughter has been having the same problems since she was 16,shes had all the usual blood tests,and we have gone so far down the road,but i am holding back,becuase i am hoping if she does(and i really feel she has ms) that it will stay quiet for a lot of years yet ,
my son also started with similar symptoms at the age of 18 and hes had 2 quite bad episodes, with loss of vision in his only good eye(hes blind in the other one)and not being able to stand,he went to a neuro and has had brain scans, a few years back, but hes not too bad at the moment,so for now he likes to think that he doesnt have MS,
It broke my heart in two, and still does to think they have ms,and like you i couldnt stop crying,for a long time,its so hard to know what to do for the best, but you know your children the best and you will know whether to tell them or not,
With my son, when he first started with the symptoms i pushed it to the back of my mind, and ms was never mentioned, and i thought to myself, i will wait for him to ask me, which in the end he did ask me, if i thought it might be ms,and i had been keeping it to myself for many years,( as hes 34 soon) so you can imagin what my reaction was, after keeping all the pain in for all that time.
i told him i had suspected it for a long time,but didnt want to frighten him,and he understood,why i didnt tell him, i also had my own reasons too, i didnt want people to think i was being neurotic over it, when i first started showing symptoms, when i was a teenager up until my ms diagnosis,i was labeled as being neurotic by the gps,no one would ever take me seriously, until my diagnosis,and i was left feeling so frustrated with a lot of people, medics and family,so i soon learnt not to mention a lot of things,and i know when i mentioned it to my dr, when my son was going for brain scans and seeing the neuro,he thought i was just in a panic, when infact i am the most calm person in a crisis, you could imagine.
The drs say our family would be just unlucky if there was 3 of us with ms, but i know of families with more than 2 or 3 with it.
So i keep most of it to myself,which isnt easy, as you know,and pray to god that a cure will come in my childrens lifetime.