Well, i have to say, I agree with your FH.
It sounds like you have given her plenty of time to get the simple measurements you need. If for whatever reason you havent heard from her by monday, I would just call her, and go on with things without her.
Just tell her that you have come down to the wire, and you are sorry for everything going on in her life right now. Hopefully things will be straightened out for her by your wedding date and she can still come and join in on the celebration of your new life.
I know its so hard, and its easier said then it is done... but you still have a wedding to plan, and deadlines to meet. I would also then maybe send her a sympathy card or a just because card and let her know you still care and are thinking about her.
Good luck... just my little ol' opinion ... you do what you feel is right in your heart.
Rachel