Blood test results

Due to see endocrinologist this morning. Looking at results. In October 2014 before treatment TSH 4.56 (0.270 - 4.2) FT4 13.78 (12 - 22) FT3 5.00 (3.1 - 6.8) TSH went up to 5.87 NHS test Nov so doctor started 25mg levothyroxine but refused to increase when TSH dropped below 5. Started Nature-throid Feb been taking 1 grain to April felt ok TSH 0.68 no other thyroid tests done, Cortisol 9 am 702 (150-720). Was told to increase to 1 1/2 grain never managed this, new batch NDT never felt right since but other health problems, also started HRT for 24 days at same time now stopped. My latest results show TSH 0.295 FT4 11.7 FT3 4.5 (same ranges) My endocrinologist has suggested that I am at the point of overmedication, my question is why have my levels of FT3 & FT4 dropped since treatment began? Any advice welcome.