Lepus, I'm glad you're OK now. I'm certainly not a doctor but all I can say is that I think you should listen to yourself first and foremost. If your body is saying 'I've had enough, here's some pain to let you know that it's a good idea to slow down' then you should listen to that.
And that "ride coach" aint no ride coach, sounds to me like he's more of a promoter with a vested interest ahead of what's best for you. Unwittingly, so are others you are talking to, by the sounds of things. I'm sure that if you explain to sponsors that there's medical reasons why you can't do the ride they will understand and if they don't then screw them, they don't care if you get hurt, you don't need that. Ultimately your health is far more important.
Gab.