Friends never seam to last, now im here crying in pain every day?

well, i dont seam to know what i did wrong, the kid was 7 i was 18 but he had adhd, and so did i, his mum asked me to help her with him so i did just that afterall my brother is her best mate so ill do anything for my brother, we was attached so close, so good friends he told me everything i tought him about life, love, respect, and it was pushed in my face, some one wrote a note to soshal services, about my brother, a few days later soshal services dragged me into it, because i was spending the most time with the kid, after a while they said no contact, or maybe suppervised, so i was seeing the kid for a little bit, then the day came, the day of the meeting, i got a phone call from his mum, telling me i must leve her house, i asked why, she told me the meeting didnt go well, i started to cry knowing full wall what was said, and i was wright contact was stopped FOR GOOD, i walked around the house for a while, and whent into his bed room, made his bed, and put a pic of me and him on his pillow, i whent down and whent on the laptop, i wrote a note to his mum and the kid saying "i'm sorry, i let the kid get attached, knowing that this would happen, because it has before, i was selfish over you and him, i should of walked away and not got to involved, but the kid was cool, and we both needed friends ill never say good bye, just ta ta for now, and i hope i'll see you both again" i looked around one more time, and i was still crying, i walked out the door and locked it, i looked at the spare key that his mum had gave me, and i took it of, and posted it in the letter box, i walked home and cryed i ran strate to my room and took it out on my brother, now im sat here, lonly crying still, and this happend weeks ago, it's been 3 weeks since i ant seen him, and it's destroying my life, every wehre i go remind me of the child, i tryed to get with my mum for a bit, and his mum told the kid i had moved away because i dont want to know him, i keep getting told that soshal service will be in his life till he is 16, i dont know is it true ? help me, i'm lost, and i'm so alone, is there ant poems or advice.