Periods problem. By less please help me!

My period get smaller and lighter And I also gain weight I just visit my doctor for this she done all the test but every thing is normal in the test kindly suggest I have blotting problem may be is just because a have kidney stones in my gallbladder and because of this I have to remove the gallbladder it's been 2years Is this a big problem or a normal I'm getting worried because I used to get normal period always it's from 6 to 7 last months I'm suffering from this problem I'm not married yet when I consult with my doctor she told me that stop eating any outside food and have a regular exercise will help u out I'm getting no answer in proper way if nothing is there they why my Periods get shorter I usually get period for 4days 3days with proper flow and last day is little less but now only for 2days and that also by less please help me regarding this