I also have an "invisible disability" and it is SO heart-breaking/ soul-breaking/ violently depressing when people won't believe you. Sadly, that is more often than not. I also do things that my doctor probably wouldn't recommend but I figure that the CONSTANT pain is so great that the consequences aren't as important right now. That doesn't mean I'm "faking" it-- it means that I'm dealing with it as much as I can, but I'm not perfect.
I haven't always been a fan of GG, but I was CRUSHED when she was blind-sighted and accused of faking her illness. I know how much pain that causes, especially when it comes from people you love and trust and hold dear.