Help!!!

I am feeling very fat.... whale like actually, I have had very light periods for the last 4 months, I am now lactating and it is increasing, my boobs feel very heavy at times but every pregnancy test I have done is negative. I have been checked by the dr for everything premenopause (I will be 40 soon) and it is all clear, no cancers either and everything appears to be normal.

Any advice on why I feel pregnant would be great