You were overtly hypothyroid 3 weeks ago with a TSH of 17+, so you're probably feeling really poorly at the moment. Try to rest as much as possible
Usually when first started on levothyroxine, your GP will re-test your Thyroid Function again in 6-8weeks. It takes that long to reach a steady level in the blood. Then depending on that result you will be given 25mcg increases in dose until your TSH is around 1. That is the TSH that most hypothyroid people feel comfy with, despite some GPs being happy when it is merely in range
So always ask for the actual figures at your reviews and make a note of them, better still ask for a copy of your results.
Remember to take your levothyroxine on an empty stomach with water only. Wait an hour to eat/ drink afterwards. Take levothyroxine well away from iron-containing tabs/liquids, as your levothyroxine won't be absorbed properly.
It may take a year for you to feel recovered. You will have been unknowingly hypothyroid for a long time and it will take that length of time to recover. However, you should feel increasingly better every 6 weeks after an increase in dose.
By the way, there is a link between Hypothyroidism and low levels of Vitamin D, Low haemoglobin, low ferritin and low B12 levels. Has your GP tested all of these? Even if the results are in range, we hypothyroid patients need the results to be high in range, with supplementation if necessary, to feel well and for our thyroid medications to work properly.
Low levels Vit D, Haemoglobin, B12, ferritin levels can cause muscle aches and cramps; xx