Hey. I was only diagnosed in may but have had symptoms for years been over weight since having my kids and always struggled to get anything off. I would go to slimming classes and gain weight.
Loosing weight will take time. And will be virtually impossible until you are at optimal levels.
So as regards to your under active thyroid.. it takes quite a while to feel well. I was diagnosed last year and I'm still trying to get my bloods at a optimal level. It's important that you understand it is a slow and frustrating process.
Many of us do well on levo some of us don't.
There are some extra tests that are recommended to be carried out
a lot of symptoms can be due to being low or deficient in some vitamins.
Being under active means that you do not produce enough hormones.
Our brain (pituitary gland) tells out body to produce the hormone T4 which then converts to another hormone called T3. T3 is tge active hormone and it is distributed throughout our body to help us function.
Being under active means your body doesn't do this
Your doctor will generally only test TSH and FT4 and you may struggle to get other things tested.
There is loads of information on thyroid uk to help you through these early days.
It is normal to have your bloods tested 6/8 weeks. It takes this long for the hormone to build and store in our system.
When you have your bloods done Tey and get the earliest appointment between 8 and 9 am. Fast only drinking water before your bloods and not taking any meds for 24 hrs before your appointment. This will give you the most accurate reading.
Once you have your results post them on here and people will help you understand them. Make sure you put ranges on too as they vary with Labs.
Hope this helps and I'm sure someone with more knowledge will also give advice