Trying to keep this reply short - always a struggle this. Staged and carefully calibrated reveals with regards to one's personal history consistent with maintaining reasoned boundaries versus suddenly divulging core trauma that predictable overwhelms a listener seems best. Alienating people for letting the gates slip consistent with rushing connection is a difficult inclination to throttle back, whereas certainly I've made a great many mistakes learning what I must to moderate expectations and calculate what to divulge and at what pace should it even be worth the bother.
Appreciate too that privacy has it's value; i.e. not everyone has to or strictly needs to know. Total exposure can translate into total trauma all the time, whereas self-preservation can sometimes be best served just to blend - presuming one can or might recharge in safe company decidedly somewhere else either in-person, by phone or via letter writing. Not everyone is going to have that depth of social support, but it's important to calibrate expectations per environment lest too much exposure be risked...
If one is in the habit of just unloading overwhelm in a professional setting behind closed doors, there's a danger that one will assume that casual interaction with others can be patterned upon the template of a patient/therapist dynamic when it just isn't necessarily the case. Best friends, closest associates - yes, but a great many others and for just interacting with the greater mass of humanity also in pursuit of the spoils in life? - no. Reasoned outbound boundaries takes time to develop, whereas more sophisticated inbound defenses take time for 'us' to develop consistent with not being taken advantage of and affording return blows if circumstances demand it. Boundary work, boundary work, boundary work...
How to pace things in the presence of those thought worthy of the extension of trust? Sometimes it's a matter of letting slip short stories telegraphing certain felt lacks in terms of what was experienced in life versus what others may have been afforded and subconsciously presume is just was there for being afforded normative care and support when it was most needed. Indeed - difficult it is to relate to so many when and at a glance they seem to function so much better (appreciated here as something akin to a smoke and mirrors PR thing existing across a continuum), whereas hard it can be to mask unpleasant awareness concerning what wasn't present back in the day stretching into the present.
It's possible to afford a measured counterpoint with regards to the gleeful and oblivious cheer others might offer up short of taking pleasure in being a sour spoilsport, although indeed - it's a challenge to calibrate consistent with knowing what and when to interject an observation or really to say anything at all. I worked as a public librarian where family-centered cheer was on the menu every day of the week, and no - I didn't cope well for all I could offer up and reflect upon concerning my own life was a vacuum of care and makeshift support soon exhausted. Not an authority here then, but hoping some of this might help...