hoplessness?

for about 5 years now i have had a struggle with depression, and only in the past 2 years or so have people found out about it. i’ve attempted to kill myself several times but never found the strangth to do it.
when people first found out about my depression they where absolutely shocked. It didn’t make sense to them, i was always the one helping other people with their problems. Hell i wanted to be a social worker or child psychologist for the sole reason of helping people with those problems. But now…. now everything just looks bleak.
today after a fairly minor argument with my parents i held a belt up to my neck once again, planning on hanging from the rafters.
first i pulled the belt as tight as i could against my neck, feeling little to no pain, but i was still able to breath.
i know hanging is not a good way to go, hell i know sometimes its downright painful, but at that moment it seemed like the optimal choice.
i dont know what to do any more, the last time i felt content with anything was 3 months ago, and since then i’ve been cheated on, pulled out of school, and left to sit in my basement feeling sorry for myself.
i HATE this feeling.
it feels like all thats left in my life is to put that noose around my neck.
ive lost 20 pounds in the past month due to lack of appitite, i can’t focus on anything for more than half an hour, so school is still out of the question, but all i feel is pressure.
my parents think im going to get better, they think im going to be able to go back to school and back to work. they think that im cured and im just being lazy by sitting in my bed, but quiet frankly its hard to even think about doing anything.
as a quick fix ive been using pot to try and cope with issues, but it no longer works. The town never has any and when it does i lack a place to smoke it. In the past it seemed to calm me down to the point where i wouldn’t hold that noose up high, but now…. now it just feels like an escape, and i know thats not healthy.
Im out of options, i would HATE to call a self help line because i don’t like my family worrying about me and they would be able to hear me talking and crying upstairs.
i can’t really find a purpose in life anymore, anything that makes me happy is slowly slipping away.
i need help.
and thats why i came here.
i don’t know why i feel this way, i really shouldn’t. ive lived a happy life so far, and have great parents who atleast make an attempt to help, but i do.
i really hope someone here can offer some sort of advice.