Worried That You Might Have A Personality Disorder? Mental Illness? Trauma?

Sometimes labels can drive us away from healing, because who wants to be stamped with a disorder? The truth is all humans are susceptible to disorder, emotional dysregulation or mental illness. Finding healing is more important than the label.
In order to heal, we need to somehow identify what's going on, so we know what to work on and why. We can do it without labeling ourselves, we can simply find out what we're feeling and doing that's not on the axis of "healthy", and find ways to heal those things.
Those who have dealt with painful, stressful, or scary events in their past, especially ongoing relationships, often develop certain coping mechanisms to deal with the situation their in at the time, but that don't work very well for the rest of life, when there's no huge crisis or danger. Those coping skills during "regular life" are much like carrying a semi-automatic weapon, a bullet-proof vest and a shield to the grocery store; unless you live in a literal war-zone, you don't need to bring it; if we feel like we do, we're either in the wrong place, with the wrong people, or it's a coping mechanism from the past that really needs to be identified and healed. Or bringing a giant net everywhere one goes to "capture" new friends or lovers, or a stun-gun, or candy and gifts to lure them, or a conductor's wand to boss them around. That's obviously not the way to make real friends, or develop a healthy romantic partnership.
These coping tools and weapons are also manipulative ways to do business, and those with true inner integrity don't want to use those, they want to make an "honest living", and create healthy relationships.
Identifying some of these developed coping mechanisms can be difficult because they can feel embarrassing to admit we have them, because we don't want others to notice (especially if they're prone to bullying), and also because it's hard to look at one's own back, and inside one's own head. Also if we don't know we're doing it, how can we know we're doing it? We can though, and once we get rolling it can actually become interesting, even fun, and definitely liberating.
A few basic coping mechanisms that many people develop are:

Retreating when stress, anxiety, fear, or discomfort is felt in any situation.
Making up "reasons" for one's retreat that are either completely false, or psychosomatic. (I have to go, I'm late for... I can't come, I have to... I can't go to work, I'm sick again...) The body and mind is very, very good at "getting us out of" stressful situations, it can even make us sick if that's what seems to work.

Making sure we are only dealing with one person at a time, so when we're with one person, we make sure we're not with another.

Catering to those who make demands on us to avoid and alleviate the stress they cause when we don't give them what they want.

Shutting out those who do NOT make demands on us, in order to cater to those who do (to avoid stress, and avoid jealousy coming from the "demanders")

Arranging our lives so that we can be available to those who make demands on us, or who have taken over the driver's seat in our own lives. We often do this and then "hate" our lives, and can't seem to make our lives better.

Hiding our actions, lying.

Holding onto people who we don't really like because we can't stand the pain of separation, and are afraid to risk rejection.

Making sure we "fit in" with others in order to avoid their rejection or bullying, or in order to manipulate them into "liking us".

Making ourselves the "boss" of other people in an attempt to make them into a subordinate, so they'll feel obligated to stay with us or "look up to" us.

Giving unsolicited (unasked for) advice, forcing "caretaking" on others, jumping on opportunities to treat others like they're ignorant, weak, or incompetent in order to get a feeling of importance or capability.

Jumping off-subject, off-topic, the moment we feel discomfort, or feel bored.

Seeking adrenaline-rush by over-spending, driving fast, dominating others, being hostile and aggressive, or other behaviors.

"Self-medicating" within the frame of self-pity.

Keeping emotional injuries "open" because healing them means letting go of certain things like identifying ourselves as wounded, and therefore having an excuse for rage and other behaviors.

Labeling others as either "good" or "evil"

Triangulating; gossiping; creating factions and cliques; trying to ostracize certain people from larger groups we're in.

Trying to separate people from one another, or keep them separate from one another.

Being passive-aggressive, hostile, and/or retaliating toward anyone we feel envy or jealousy toward.

Avoiding doing things to actually heal ourselves; dropping things that were working to heal ourselves and going back to old habits because it's more comfortable.

Caring more about our own comfort than the actual needs of others in our lives; treating others without respect because it's "hard" to behave in a respectful manner.

Feeling guilt and/or shame when we're doing anything other than catering to certain "demanders" in our lives.