I Had A Total Thyroidectomy 30 Yrs Ago For Thyroid

I had a total thyroidectomy 30 yrs ago for thyroid cancer. I take Synthroid 125mcg. I have gained weight, mentally feel foggy and unmotivated, my hair is beyond thinning. I believe I need a higher dose. In the past I have required 150mcg. I asked my PCP if I could have my med. increased to 150mcg. She said every Sunday take 2 of the 125mcg tabs. and on the other days take one tab. I am not comfortable doing it this way. My Free T3 is 274. My TSH is 0.23 Also I am on Prevachol 80 mg per day and my cholesterol is 223 despite exercise etc. I am post menopause. I think I would feel better on a higher dose. Would really appreciate your input. Thank you.