You remind me of how I've been, and I'd like you to feel better, nobody deserves to feel as you do.
The things you think should be good and a comfort in your life, having people that care, and being bright and so on are basically irrelevant when you have thoughts of taking you life
You have summed it up when you said "I feel worthless, hopeless, trapped and can't see how things can change."
Exactly like I was. My mind narrowed its focus down until all but a few horrible hopeless facts were all I could see.
Yes it is frightening to think of what one might do with the opportunity when one feels so down and hopeless. Also I found at those times by brain was sort of locked and I could not think clearly and see alternatives.
As an aside I did not get better until after I had told of how I felt - it was at that point my treatment started for the right thing, not the watered-down version I'd been describing.
Anyway when one thinks one might take one's life it is extremely handy to have something you can reach for that takes no brains or decision making. I would very much recommend a safety plan. These is an excellent free one to download here called BeyondNow - it fits on a smartphone so you can use it anytime:
You fill it in in advance. Not only does it have the usual things like emergency contacts, but also a section on what you can do yourself. This is excellent and can be filled with all sorts of things that may distract, amuse or give you a lift. I have links to YouTube videos, music, books, movies, suggestions for walks and tons of other things. You may well have different.
You need not fill it all in in one go, in fact I could not and needed the help of someone that knew me well to help me remember what had been good in the past.
I've found it realy can be a life-saver.
One of the crisis entries I'd include is a place I've found to be more than helpful, it is the Suicide Call Back Service,
1300 659 467
They can be talked to more than once without repeating explanations, have web-chat if you prefer that, and they do not panic, but are understanding and realistic.
I think I've said enough for one post, please do come back and talk more, I'd like that