Just found out I'm pregnant last week so am about 5.5 weeks. Dr has put my thyroid medicine up from 50 to 75mg daily to try to reduce my TSH levels from 3ish down to 1ish. For the last few days I've been having severe headaches, sciatica type pain down my bum and legs with very achey muscles, waking in the night a lot and not able to get back to sleep. Do you think this could be the thyroxine or pregnancy? Am in agony and have really struggled to look after my toddler this weekend.