A.M.
Hi J.. I too was very concerned when it came time for my daughter to receive the MMR. I separated them into three shots, as recommended in a book by Dr. Stephanie Cave called, "What Your Doctor May NOT Tell You About Children's Vaccinations". We did the mumps shot first at 12 months- the measels shot @ 15 months- then rubella we did after she turned three (I waited so long b/c I was pregnant w/ our 2nd). Not all offices have the shots separated so you have to ask. I had to find another doctors office to do it for me and when it is time for shots, I bring my daughter to the "shot doctor" instead of her regular pediatrician. When it comes to shots, you have to do what you are comfortable with and go with your gut. Be informed. I truly found the book by Dr. Cave VERY helpful. Lastly, I hope your girl gets well soon!
Good Luck! -A.