Hi op!
You can carry on for a long time being hypo. It does drain lots of resources though, esp if you've been like that for a while, so recovery may take time too.
Health unlocked is good, but I can summarise a lot of what you'll read there.
I really really recommend getting the BMA book by Dr A Toft, on Amazon. Not least that it explains the optimal meds and blood results we need, which SOME gps MAY not be aware of or consider necessary. You can wave it under their noses
, stamped BMA so 'kosher'.
It also explains tests clearly. And explains treatment, including why SOME are trying combo t4 and t3. T4 (thyroxine) however is easier to keep track of so if you can feel well in that it's better (more stable as longer half life) but, consequently, blood results should be optimal. Not mid range, unless you feel best like that. GPs SHOULD ask you how you feel at dose levels, but you need to be aware it can take 3 months to actually feel better sometimes.
It will take a long time to feel well I'm afraid. A dose change can take 3 months to fully show in blood tests or in your body, due to the long half life, though you can be tested after about 6 weeks. So you can see that getting the meds right can take time.
As cholesterol is high they are raising you slowly to avoid angina issues etc.
Keep a record of your tsh, any t4 or t3 results (unlikely tho to have t3) and your cognitive ability, muscle strength and general well being. Ask for these each time. A Tsh of 3 is classed as normal, but some would struggle. A Tsh of 0.5 is also normal but you might feel great. So good to find your ideal.
Quite a lot interferes with absorption of thyroxine, so read how to take carefully. You can miss a dose and take next day no problem due to long half life.
Smallest tablets are 25, I find I have to adjust my dose to 125/150 alternate days to get the best level for me.
Definitely ask for ferritin to be checked, vit d, b12 and folate. Low thyroxine affects muscles; theses need iron to recover (and b12). These do need to be optimal but gp might not think about it. I've suffered at ferritin was around 50 for a couple of years - borderline - but it became clear I needed it to be 80+ to feel well following a thyroxine slump post preg.
The endo I saw agreed and things I've read on health unlocked and here seem to indicate 70+ is best. My gp now comments my iron is normal -I think it's usual that actually ferritin gets much lower for there to be issues,but for us it's best to be optimal. (Iron interferes with absorption though so take apart) best to get test and discuss with gp.
For now you might find taking ferriglobin and another vit d thing helpful, but if you're really low you'll need prescribed.
I think your family just need to know it will take a while for you to feel better. You may find you notice how I'll you were when you actually get better, iykwim?!