I withdraw when I'm overwhelmed with something I can't immediately figure out and when I don't entirely know what my thoughts/feelings are regarding a relationship. I guess this is a level of stress...sort of...even though externally I'm still fine going about my daily life, job, etc. But the uncertainty internally just results in my having *NO* desire, really, to interact with anyone on a social level - I just feel so off-kilter or overly emotional/confused- especially with the person/relationship I might be tossing around in my mind, trying to make headway out of. I just don't want to talk with them; and I think the state i am ins' comment on *resentment* is interesting, as that's one of the emotions that I don't want to taint the interaction with, thus withdrawal is quite preferable, esp. for the other party, because frankly I'm not in a positive frame to even want to talk to them.
So the withdrawal is primarily because I don't know yet what I think/feel, with possible negative emotions such as resentment. I need to figure it out on my own and figure out what I want or need, etc, or whether I'm overreacting, or under-reacting, being fair or unfair, reasonable or not, justified in my feelings, is the relationship 'working' for both of us or not, am I being ridiculous to even fixate on all of it in the first place......need time to sift through all of that.
As the-state alludes to, the withdrawal can easily lead to more imbalance, even though it is my natural instinct and I WANT to crawl into my shell and don't WANT to interact with people. But yeah, often-times being pulled out (assuming it's by a person other than the one I'm mulling over in my mind) or making a conscious effort, ourselves, to stay active, exercise, more engaged with the external world, can be of more use than going into analytical introverted-cave-antisocial mode.