Underactive thyroid new diagnosis

[trumpisaflump]

I’ve had the most awful abdominal bloating over the last few weeks and saw my GP on Wed to hopefully rule out anything sinister. He called me yesterday afternoon to say gladly the blood test for ovarian cancer was negative however my thyroid levels were almost undetectable. He has started me on Levothyroxine 100micrograms daily and I have to get my bloods checked in three months to see how this dosage is working for me.
I’m obviously so relieved I don’t have anything sinister but this has now opened up a whole new world of internet researching 😆 I had hyperthyroidism in my twenties and my GP said it can be common to switch between conditions as the thyroid gland burns itself out!
Can anyone give any advice on managing this and when I might start to feel a bit better? I always feel cold but I but don’t have any weight problems and am probably underweight.
Thanks

I started to feel a bit better almost immediately (was feeling shocking before) but it was probably a year or so before I stopped improving

Really? That's great you started to feel better straight away. I'm hoping I'll feel less tired soon.

I'm delighted to see that your GP has given you a proper starting dose, so improvement should be fairly rapid.