Low hb&hypothyroid. Whate problem i hav.

I hav 3 kidney stones.I have hypothyroidism since 7years.i take medicines.now tsh 0.57.but from 4months I have black  loose stool 2 times with abdominal pain.i check all blood tests cbc diabetes  endoscopy, colonoscopy(biopsy) , occult blood stool usg abdomen ptothadene time test ana profile test  crp test hb is 13 gm all tests r normal .doctor prescribed sarotena  tablet   for ibs .from 2 months I have severe fatigue tired some times chest pain   loosing 2kgs weight from 2 months &4 small pichets are in my chest &stomach ,itching scalp shoulder arm pit vagina also. I hav low bleeding dizziness  in periods with abdominal pain ever this happens before .I  checked hb it is 9 gm. Iron ferritten are normal.but b12 is only 10 ultimate is less are than normal. whate problem I hav .this month I do not have periods . please suggest what tests to be done.i have any blood cancer.