What exactly do you mean by that? Do you mean when you walk past sum 1 and u talk to them? Or people who hav come into your life n have gone?
If its the first thing i said, Then thats a problem i dont think anyone on GS can help you with. However if its the second thing i said then you form relationships in life and some people r sensitive and it hurts them badly and cant get over it for years and years some people can jus get over it n move on str8 away. Its life and you have to deal with it.
But i dont think you shud let it take over your life, Dont believe everything everyone tells you!! If your in a relationship try not to give all of your-self too quickly, Giv it time to see if this person will be there for you in the long run.