I’m really feeling down

I'm 16 years old and about a year ago i lost all of my friends in a big incident, i dropped out, I have and i have no one to speak too. my family's not that bad to me, well my dad hasn't ever really liked me. I'm starting college in 2 days and the course is full of really really stupid people/ borderline retarded, because it's a course you don't need any qualifications for. I have been thinking for a long time about killing myself but never felt like I was on the verge of doing it, right now I feel so close to just going to the nearest big bridge and jumping, the thing that used to scare me was the obvious scaryness of the situation but recently Ive just lost my fear and any other emotions at all, I cut my arm with a knife the other day and it scared me, not because it hurt or the blood, it was because how easy it was and how it didn't hurt at all, I've tried doing it before just out of curiosity when I wasn't even depressed, just to see how much it hurts the people that self harm, but I got too scared then and couldn't. I know this post is put up soer sloppy and without grammar and all that but I just thought it was worth a try, sorry if it's hard to read. Recently my brain has just really darkened, I get nightmares every night about either seeing myself with my limbs cut off screaming or forced into worshiping some kind of awful blood demon, I also get nightmares about my ex who I mistreated cheating on me and laughing at me and making a lover out of me, or more of a loser out of me I should say lol. Everything about me is so dark and saddening now and i can't even complain about it cause my life is only bad because I've made it this way, I am a bad person and I've done really bad things my whole life, I'm either a narcissist or had bpd. I Just feel like this gross little piece of pathetic nothing that doesn't deserve to even smirk, cause I am and my old friends would say the same about me, I just stay In my room all day for for weeks sometimes. I Just want someone to fucking love or something, I'm the type of fucling person you'd see on the news whos done something awful, like those weird fucking school shooter incels, I don't wanna be like that but I probably am experiencing the same thing as they do before they break. Who the fuck, fucking cares any way. Bye