I’m new to accepting BPD and still trying to further understand why I’m this way. This isn’t everything, just currently what’s on the mind 

So throughout my life, I’ve just been that one guy no one really notices or ever wants around. I can’t speak for others and their intents but only what I’ve always been left with feeling (hopefully that makes sense, makes sense in my head). 
I have zero friends and pretty damn tired of it. I have no idea if this is selfish or wrong. But I’m tired of feeling like I’m the only one that tries. No one can ever reciprocate slightly. I constantly try and converse with others, make a friend, be there for others, help within my capabilities or sometimes (pending how bad I feel and want to help). Go further and damage my finances because I feel like everyone deserves help and if I was in their shoes, to hopefully someone can treat me that way someday. The shitty part about this is I love helping people, BUT.. it’s usually the only time someone talks to me. Is asking me for help with someone. I never want or ask for anything. I’ve never felt accepted or felt I belonged anywhere. And it would be nice to experience that for a change. Someone to just be like “hey dude, wanna go for a drink?”.. wanting to be included in something and I would appreciate that more than they could imagine lol. I’m always left feeling and thinking “what is so wrong with me?”. I’ll be sitting at home with my dog and cat and then a thought of “wow, If I somehow died right.. no one will know for weeks”. That, my acquaintances, is a super shitty feeling to deal with on the daily. (No im not suicidal). Just a thought and feeling. That’s just in the trying to find friend realm. Dating wise, I don’t know how to meet or attempt to date anymore. I’m always honest and all of that. Last “girlfriend” found a sugar daddy that wanted to pay her a good amount of money for sex. So I was ghosted on that and made to be that bad person for being angry and hurt. Mostly moved on from that, that’s the life she ants to live. Whatever, just wished I wasn’t so easily dismissed. EVERYONE leaves me if I ever get to a consistent point. I’m now too scared to even try and walk up to someone and ask them out. And then trying online. No one can even talk to me on that. Or the ultimately rare chance someone does. I get stood up. Always left feeling no matter what I’m not good enough for anyone or anything. I get medically discharged out of the army 7 years ago after service 7 years and live off of disability and SSDI because no one will hire me. I’ve tried nothing but to be a good person and friend to others only to hardly exist to everyone else. Feel like I’m only destined to be a failure, unwanted, and ugly. No I haven’t given up completely, I battle that everyday. What keeps me going is my son. Would do anything for him. I’m just venting to get this out because I have no one. If any of y’all care to respond. Much appreciation ahead of time. Even if y’all tear into me for something I’m unaware of. Much appreciation. Just hoping one of these days it will end or I find an honest answer to what think every night. “Why is it so hard just wanting to be apart of someone’s life and equally be in mine”

Apologies in advanced for the long rant