What’s wrong with me that people who get to know me realize I suck and they go away?
It is disheartening to learn that people are behaving in such a rude manner to you--especially at work. A part of being human is our need for social contact; however, managing relationships can be frustrating at times--especially when we do not understand why things keep going wrong. I do not believe anyone who is looking for help to manage relationships or learn more about themselves "sucks," so I am going to provide some of the things that commonly contribute to problems with relationships.
People can be drawn to the "wrong" person. This person might seem interesting at first and then we might realized that we are unhappy with the relationship. It is my belief that we can find ourselves in this situation due to what we saw in our family of origin. As we become aware of the different family dynamics, we develop a set of standards for what we will not tolerate, what we are attracted to (not just physical), and then there is the part that remains outside of our awareness. For example, we might have a family member in our immediate family that has some mental health issues. As we grow up around this, it might lead to having a comfortable attitude around other people with mental health concerns, to the extent that we can end up in relationships that are not healthy for us. This is one aspect of the problem to consider, are you attempting to develop relationships with a type of personality that is not a good fit?
Another problem that can occur in relationships is communication. Some people seem to be natural communicators and we might think it is something you either have or do not; however, communication is a skill that can be learned. Communication styles likely develop from our experiences in childhood and our personality. Whatever your style of communication, you can learn new skills to make it easier to engage with people in a positive way.
Being a people pleaser comes with its own set of potential problems. Pleasers might over estimate the stage of the relationship in their wish to help others. In extreme cases, others might see this as overstepping boundaries and that could lead to them misunderstanding your intentions. As a pleaser, it feels good to help others and can be frustrating or disheartening why our efforts are not appreciated, which can lead to feeling rejected or doubling down on our efforts to help the other person. Learning how to set good boundaries can be a way for a people pleaser to establish good relationships and boundaries can be learned.
I hope this is a more helpful way to look at what is going on. Without more detail, it is difficult to predict what skills might be most helpful for you to learn, but I would encourage you to find someone who can work with you to build a better understanding of how to develop healthy relationships. Just you asking for insight is a good indication that you are willing to work toward this goal. I wish you the best.