Levothyroxine Sodium and sodium

For the last year and a half I have taken Levothyroxine Sodium 50mg, now increased to 75 mg. I have gained a great deal of weight and developed arthritis in both knees. Some days my knees hurt so bad I can hardly get out of bed. Since my medication was increased to 75mg. I have been itching like crazy. It is not continually, but at times I just go into an itching fit. Please help! Is there any other thyroid medication that works without all the bad side effects?

i have just been diagnosed with auto-immune hypothyroidism and have been prescribed 25-Eltroxin sodium. I've also been trying to conceive. At the time of starting my medication I was coming up to ovulation. On day 13/14 of my cycle I was worried as I noticed significant breakthrough bleeding (bright red/with clots). I am waiting for my temperature to go up to show that I've ovulated but it hasn't happened yet. My bleeding is lighter now, 5 days on and brown in color. Can anyone explain how/if thyroxine can cause this as I've never had mid-cycle bleeding before. I have been bleeding for 4 to 5 days now and its not as heavy as it was. What is happening to me?