It's Wounding 101 really...taking the message of a wound and adding it to our grid to apply to other situations. What do I mean?...we suffer a tough experience (hurt by someone we love), we take the message of that wound (they thought I was worth rejecting, etc.) and we carry it into other unrelated situations (he/she/they must be rejecting me too, etc.).
What we do with that can take a variety of forms. Many stay perpetual victims, always assuming rejection from others. Some quickly form judgments and overreact with negative self-talk, "pity parties", withdrawal and tantrums. Some become aggressors...either by rejecting (or leaving) before getting rejected or baiting people to see what it would take to be rejected (and then acting like they don't care when those others have finally had enough).
Being the one that someone with rejection issues is targeting (or just being someone in regular relationship who cares for a person with this affliction) can be really overwhelming. I get to the point where I just want to scream, "STOP IT!!!!...it's not true that someone is necessarily rejecting you by not inviting you to something, having other things to do, not needing your help, not being super communicative at the moment, being more intense than you, and on and on and on!!!!!" Sigh. Alas, we all have to decide that on our own...and it sucks waiting for that.
On the flipside...bringing this from the realm of "others" to ourselves...it truly is hard but imperative that we face, nurture and release our rejection issues. It's the only path to healing...and a life less driven by our woundings. Real moments of rejection are painful. And from my heart to yours...it wasn't ok. Truly, though...going after others (assuming rejection all the time) is NOT a way to defend ourselves from a painful moment a long time ago.
I have to be very intentional with my rejection issues sometimes. I have to purposely try to view others without applying my hurtful experiences from a few. In the moments where that's difficult, I'll actually take some time to pull a particular hurt off the shelf (the one that situation is bringing to mind) and really let God speak to that experience. I'll ask Him what His view of me and that situation is and ask that His message now be what reigns true in my life. I'll ask Him to help me forgive...and to let go. Seriously...He does an amazing job of breathing new life to those dead places. And slowly...with time and intentional practice...we can become more secure in our worth and live a life of more "response" than "reaction".
No one's worth rejecting...but life happens. More than anything...we need to let God's view of us be the truest thing in how we view ourselves and the situations of life.