i can't stand feeling like this anymore

ive been through a lot in life, but by most metrics ive made it out and have a relatively good life. but for some reason, its like this cloud always seems to follow me... and now it really feels like its engulfing me. i feel like im becoming so detached from reality. my friends don't care enough / dont wan't to listen when i need someone to talk to (and i can hardly blame them, who would want to hear the ramblings of some depressed person). i just feel so horrible all the time, thinking about how meaningless this existence can be, feeling like i shouldn't even bother going on, and i hate these thoughts so much. sorry for how unstructured this is or how unorganised my thoughts are, i just can't bear to hold it in any longer, i feel like im going to snap if i keep bottling it up.