Friendships, coworker interaction and how to tell who is fake or trustworthy?

This is a problem I've had my entire life and still I don't know how to deal with it. People that have sought to have been 'friends' with me have emotionally used me as a soundboard for their woes and have not reciprocated in turn, or have asked more and more from me like emotional vampires again without supporting me or realising they are causing me distress. These people also tend to ask for money (small amounts for coffee or soft drinks from the local shop) and never give me the money back like they say they will. They go and get coffee or converse and socialise with other coworkers and I'm not invited. At the beginning of my employment less than a year ago, the same people would bother to converse with me and spend time with me. It's like they've realised there is something wrong with me and have rejected me. There is the other sort of person who tried to get me into trouble (I think) by trying to entice me into saying something bad about the company I work for or share inside jokes that make me look stupid. It's like they think I don't realise that they are treating me like a fool. Their expectation of more to gossip about is really annoying and I can only imagine they gossip about me behind my back too as gossiping is their 'normal'.

How do I address any of this while these things are happening and how do I hide this metaphorical target sign on my back? This is bullying isn't it? Although some people close to me like my parents say it's my perception. I feel dismissed by them when I raise these concerns about communication and interaction relationships with other people. It's really no wonder some people become hermits. People are inherently nasty I think. This belief is the result of many many let downs and disappointments over 30 years of experience.