Hi Huntzacksmom,
It may be possible...but it also may not be advisable.
In general, there is a limit to how small you can go safely. There are no absolute rules, but you have to leave enough breast tissue to provide an adequate blood supply to the nipple and areola. Making the breast too small can compromise that blood supply (there are many other factors that can also do so, and many of the problems that occur are without an obvious source or cause, but that could be part of it). Going too small increases those risks.
The other issue is aesthetic. Depending on the woman's frame, going too small may just not look right. The breasts should, ideally, be more proportionate after the surgery, but going too small risks making the patient look equally disproportionate as before, just in the other direction. So although it may have helped the symptoms, it may contribute to other concerns in the future. I would probably advise that you go to some kind of a D (small, full, etc)
You should, of course, discuss all of this with a surgeon who can examine you and who can give you advice in person, but that would be my general approach for questions such as this one.
I hope that this helps, and good luck,
Dr. E