I take 150 mcg of levo thyroxine daily. My chemist ran out of my usual brand and gave me, i now realise, a mixed prescription of some boxes containg 50 mcg and some containing 100mcg. I started taking 3 tablets of the 50 mcg but moved on to a box containg 100mcg thinking they were still 50 mcg. For the last 10 days at least i have, unwittingly been taking 300mcg per day. Please tell me what i should do? I feel quite scared. I dont feel hyper but i do feel a bit off colour like i have a cold coming.