FWIW, my neuro told me that by the time a person is "officially" diagnosed with MG, they have probably had it for MANY years - the symptoms come on so gradually, they are attributed to something else.
When I look back at pictures of me, I can actually see the eyelid droop starting back when I was pregnant with my first child - she's about to turn 26. It's not terribly pronounced, but it's definitely there.
And when I think back to all of the times that I was just too tired to do stuff - things that I (and others) attributed to "laziness" or "being out of shape" - I realize that the MG has been present all this time. It's a bit of a relief, actually.....
I think it is SO much harder when someone is diagnosed at such a young age; however, it is good that you have found out about it now - you can take steps to prevent serious damage to your body.
Allow yourself to REST - I know that's a hard thing to do when everyone else around you is so active. And allow yourself to get mad - it's an essential part of the grieving process. I hope that you are able to get answers very soon; then you can start addressing your health issues.