Suggest Remedy For Tiredness Due To Under Active Thyroid

Hi, I have had a under active thyroid now for over 10 years and have been on 175mg for most of that time then about a year ago it was increased to 200mg which was fine, then after a routine check up my doctor decided it needed reducing back to 175mg which was about 6 weeks ago, now I feel so tired, my calf muscles ache like mad and I find it uncomfortable to walk, I find it tiring just raising my arms to hang out washing or fold washing these symptoms are very similar to before I was diagnosed with under tyroid, I have all sorts of blood tests and they all came back normal including my thyroid, my doctor has increased my meds back to 200mg but that was just a coulple of days ago and obviously it takes some time to get back in my system but I just feel so down at the moment because of this and I dont know what to do.