I am a firm believer that your weight shifts during pregnancy. For my first pregnancy, I gained 18 pounds and was able to wear my wedding ring the entire time. For my second, I gained 23, but couldn't wear my wedding ring by about 4 months. I have lost all the pregnancy weight, plus about 10, but my wedding ring still does not fit. I always joke that my fat shifted to my fingers and my chin - both of which are larger since my 2nd pregnancy... My daughter is 3 1/2, and I still can't wear my ring. My husband bought me a larger size plain gold band during my pregancy and I can still wear that. He has been asking me to just size my diamond ring, but I have refused, saying that would be admitting defeat. :-) However, I have promised him that if I can't get it on by April (our daughter's 4th birthday and my 40th), I will have it resized...
I breastfed my first daughter for 11 months and my second for 14 months. I never associated my fat fingers with that only because they got fat during my second pregnancy, not while breastfeeding...
So, bottom line - you are not alone... Give it a few more months and the last 15 pounds before making the decision...