I just started volunteering for a cancer charity and meeting terminally ill patients who still have fire in their belly and fighting death even though it is close. it has been an emotionally charged situation for me to be in with me being suicidal like you and in hospital all the time with OD's. It has certainly given me some pause for thought. As your mind is made up and as you say it will take time why not use that time to volunteer yourself it may give you pause for thought too and if nothing else it gives you the chance to get value from the days, weeks, months before you take action. I am socially withdrawn also and scared of social environments the cancer journey is surprisingly similar to a mental health journey but with much better support networks. I found myself almost jealous of them which was weird but they are holding my hand and gently introducing me to being with people again. It certainly wouldn't do you any harm. Your age does not mean anything you are unwell and need help and are utterly entitled to get help.

GET A NEW T AND REPORT YOUR EXISTING ONE THAT IS UTTERLY DISGRACEFUL!!! You should never accept that treatment your T is a disgrace to the profession.