Hey there and welcome to the forums;
Your situation certainly seems dismal. I'm sorry about that. Being sad and isolated from friends and family can really get to you, especially when they're in the room but aren't 'there' if this makes sense. I totally understand this predicament I can assure you.
Wanting others to respond the way you'd like and being disappointed over and again has worn you down. I get that, absolutely. Can I ask if what you were told at work has any merit? Would you come across as sad all the time? Unfortunately, appearing this way can overwhelm people; they just don't know what to say.
I'm wondering if you've spoken to your GP about it. Maybe talking with a counselor or psychologist will shed some light on your situation. They're there just for you and won't talk about their own lives as friends or family do. This helps to sort through your thoughts and feelings and hopefully identify what the problem might be and how to approach things.
Talking here can be a relief too. You know, getting it all out without being interrupted and receiving empathy and support so you don't feel so alone. You're really brave to come on board and ask for help by the way so well done!
Also, if you look around the forum for threads that might be interesting to you, please join in. There's people from all walks of life probably feeling very similar to you. Talking with members can shed light on your situation. It sort of works that way; give support to receive support is BeyondBlue's motto.
I hope things improve hun. Reaching out as you have is a gutsy move and I'm sure will pay dividends. Looking forward to hearing back from you. Please take care...