I used to do this with people, always suspecting or expecting that they would turn bad. I had to train myself over time to really observe what I was projecting into them. Eventually, I became able to separate my (false) expectations from what usually happened.

In this case, it's likely that this person genuinely liked you and wants to stay in contact. However, if one is not comfortable with intimacy and opening up to another person, that can feel threatening. The fear of intimacy is another reason why one can sometimes project unrealistically negative expectations into another person, because it serves to distance them from you and to make you feel safe from disappointment or hurt in case they turn out bad. However, if you practice it, being intimate and close is kind of like weight-lifting - you can build a little bit of strength at a time and eventually get much better at it. Good luck!