Regular namechanged. I don't know why. Maybe because I feel like I'm being ridiculous to even feel this way, but I would appreciate some feedback.
I am a single mum to 2 DC.
My eldest (DS) is 19 and I am heartbroken at the state of our relationship. I completely adore DS, and have always done so, from the very moment he was born. I had such a close relationship with him, he found it very difficult to make friends (mild ASD) and I would spend hours playing games with him when no one else wanted to play with him. I am not the most confident of people myself, but I made friends with people just so DS would have some friends (their DC).
DS was never very confident in himself, and I helped him in any way I could. He is a lovely looking lad. When he went to high school, he blossomed and made a few friends. I welcomed them all into my home. We chatted about so much. I always treated him with the utmost respect and spoilt him too if I'm honest, working from dawn until dusk to give him the things he wanted (usually what his friends had). It wasn't easy being a single mum, but I just wanted him to be happy.
Primary school practically wrote him off, because of how difficult he found school. The headteacher even told me that I wasn't to think of DS as a future scientist, more a trolley dolly. 
High school was much more supportive. DS went onto college. I was so proud of him. 
Halfway through his college course, he decided to move out, get drunk every night, and almost ruined all his hard work. We spoke and he pulled himself together in time and passed his course. I sat up until 4am writing his notes up for him while he slept.
Since DS moved out, we have got further and further apart.
Now we rarely speak, and I think he must hate me although he claims that's not the truth.
Everything about his life with me he seems to see as an awful time in his life.
It has all come to a head recently. He has told me that he hated school and doesn't want to remember anything from when he was at school.
He doesn't remember us doing anything together, although he doesn't disagree we did things together, just that he doesn't remember.
He says he was always ashamed of my low paid job while he was young and felt embarrassed about it.
He has told me I'm not a very interesting person, and I think too much.
He visibly fizzes when he speaks of his job or his friends, which is rarely, but OTOH deflates when I speak of anything I have done.
He says I have never made him proud.
He never calls me or texts me and he even defriended me on FB 
because I 'liked' one of his statuses. His reasoning was that his friends wont comment now because I had 'liked' it first.
I remember his childhood with joy, he remembers it with sadness. I did everything I possibly could to make sure his childhood was happy, but he wasn't happy. I have only recently found this out.
DS is logic through and through. I am a single mum now, and when I once said it was hard being a single parent, DS said 'We all make choices, you have made bad ones.'
I have fucking failed as a parent, I have lost what I had with DS. There is lots more but this is long enough as it is, and it is shit to feel like I never really knew him, and the 'old' DS is never coming back, because I don't think he is.
I help him in every way I can, but he is just so unresponsive towards me. He behaves completely different when with his friends, they see the side of him that I used to see, but haven't in the longest time now.
I appreciate most of this is probably his ASD, and that's another reason how I know that this is it, forever.
DS is popular and has a job he enjoys, lots of friends, hobbies he enjoys. OTOH, I am single, and likely to be for a long time, and have watched my life whizz by in a strong wind, dedicating it to someone who truly doesn't connect with me, and finds it hard to give a shit.
I can't remember the last time DS wrote something other than 'To mum, from DS' in a card, or gave me a hug, or even laughed at something I said. I have kept every mothers day card/xmas card/birthday card/ he has ever sent me in a big box along with his school reports, special pictures, photos.
DS used to say I made him as happy as chocolate, but I guess he's discovered chocolate makes you fat, and therefore not very happy in the long run IYSWIM.
Sorry, just needed to write this out. Not sure there is much that is going to make me feel better, because nothing is going to bring the DS who loved his mum back.
He is supposed to be coming over for dinner tomorrow (He is driven here and picked up after or he wouldn't see me at all.) I am frightend to try to talk to him, even chit chat, in case I say the wrong thing and watch his eyes glaze over, or I cry at what we have lost.
Not sure how much longer I can try.
I shouldn't expect anything from DS, I know, but it's heartbreaking to know DS doesn't like me anymore, let alone love me. He has even told me that if I died tomorrow, he wouldn't miss me because that's part of life, you live, then you die.
I mean nothing to him, and yet I would lay down in front of moving traffic in a heartbeat if he needed me to.
Am I torturing myself to even attempt to continue this one sided relationship with him?