@rosey, I know what you mean. Someone in my group once used the term, "emotional hangover" to describe super long lasting feelings that come on later, after an event, and I said I get an emotional hangover after every t session -- even the most benign ones! I can't talk when I'm crying, and sometimes I talk about the most horrific things very matter-of-factly.
The thing is, I ruminate, and there's only so much time to process in-session. I will "tank" later that night, and stay down for days. I often put myself into what I call a "medically-induced sleep coma," where I'll crawl into bed, pull the covers up, and sleep for days.
I once had a particularly hard session right before leaving for vacation, and my T asked me if I could leave some of "that" (the horrible memories) with her ("it'll be safe with me, and when you get back I'll give it back to you"), aka, "leave it in the room", and instead, take some of her compassion for me with me on vacation.
That really struck me, especially about her compassion. I imagined myself packing her compassion for me along with my swimsuit and snorkeling gear. And I knew, as an artist, that I wanted to make her some kind of "container" with symbolic representations of things we've discussed, archetypes, other meaningful symbols, etc. So, I did just that, and she loved it. It's a small woven-grass basket with little glass bottles (permanently sealed) hanging off it. For example, one bottle has sea salt in it, another has rum from the island, another has ashes from a ritual I did on the beach, along with painted feathers (representing myself as a Phoenix), one has honey from a friend's backyard beehive, etc. One bottle is empty and unsealed, inviting her to fill it herself or leave it symbolically empty.
Anyway, I haven't really "used it" yet. I still ruminate on things outside of therapy, and don't always feel things as strongly in session as I do outside of session. But we've been working on stabilization, self-care, urge-surfing, distress tolerance, emotion regulation and other DBT (dialectical behavioral therapy) skills for almost a year.
BUT, I'm about to start 9 weeks of prolonged exposure (PE) therapy, and I intend to make good use of that container! I know I will have homework, will have to listen to the therapy tapes at home and do in vivo exposure during the week. But I'm hoping to symbolically use the container to leave the feelings of shame and self-harm urges "in the room," so to speak.
Don't know if this response was helpful at all, but as you can see from all the posts, you've struck a chord and are definitely not alone! {{{{{hugs}}}}}} if you accept them, chocolate if not! Hang in there!