Help!!

I am almost 37 weeks pregnant (36+4) and I have gained almost 60 pounds!! Obviously my doctor has raised her eyebrows at this and has implied basically that I'm just not taking care of myself/eating the way I should. I hadn't begun to pack the weight on until a few weeks ago; I eat healthy meals and snacks, I drink a TON of water, and I am really active in my job and home life. I'm worried there may be a more significant reason behind my rapid and sudden weight gain and I'm frustrated because my doctor does not seem interested in trying to find the underlying cause (she truly just believes I need to "eat better" and "drink more water" and "stay away from the sweets and empty calories"). I rarely indulge in cravings and especially lately have found it extremely difficult to eat very much at one time as baby is now taking up so much space. What do I do??