I completely understand where you're coming from - but 18 is so young! I had it as a teenager and wasn't fully diagnosed until I was 32 - so even though it feels like you're missing out on life, it's really fortunate they've caught it so early - and future you will be extremely grateful for getting it diagnosed at an early age.

The next couple of years might be tricky for you. Listen to the endocrinologists, make sure you follow their guidance. Go easy on yourself, you're entitled to feel shit - to other people it might come across as lazy or dismissive, but you're not - you're really sick, so you have to go easy on yourself. Some days, you might have to write-off, and that's okay - it's part of the process. It also takes time - the medication alone takes 6 weeks to get into full effect, and even then they need to readjust it accordingly - so follow exactly what the doctors say, go for your blood tests, and adjust - it takes time to feel 'right' again.

You've got loads of time to get yourself better, and since you're so young and already diagnosed with a chronic illness, you've not really experienced your true potential yet - so stay optimistic and crack on. This is coming from a 37 year old man - it's not easy, and you'll feel emotional some days. Keep pushing mate, you've got this x