Suggest you join the Thyroid Uk group on HealthUnlocked as a good specialist source of help.
You need to supply lab ranges with blood test results to evaluate properly where you are within them. It sounds like you are just on too low a dose of T4 still (50 is a starter dose and at least 75 more usual)
People often start feeling well with a little treatment but get worse as their body adjusts by cutting down its own production and conversion of T4 to T3 (T3 is the active hormone). It is a response to an initial dose that is too low.
If you can stick with it, increasing your dose til free t4 is towards upper quarter of range you should start to feel better. You can also check free T3 to see if that is in a similar place in the range. If not T3 or NDT may help. I know you have tried a small amount ( not sure how much) but probably too soon in the process.
Once you are being treated, TSH is irrelevant (although that is not what g.ps are trained, patient experience and common sense says otherwise) and you need to look at the free hormone levels in your blood.
Best of luck, stick with it and you should get to a good place, although it may take some time, a deal of determination with the medical profession and some self help!