Have Hashimoto's, On Synthroid 100mcg Daily, Last Counts T4 Free1.4ng/dl,

Have Hashimoto's, on synthroid 100mcg daily, last counts T4 free1.4ng/dl, S-TSH 1.2mlU/L. I am tired, tired tired. Feeling exhausted and tending to depression despite cymbalta. Continue to gain weight and am now at 174lbs at 5'3" Work full time as a nurse. 57 year old female. Is it reasonable to ask for increase in synthroid or am I doomed to this weight and exhaustion until I die?