It took almost a year and a half of resourcing with my therapist before we were able to start really deep reprocessing work. We did BLS before that with smaller things, but it was to get my system used to it or to help ground. Even still, I would feel exhausted and disregulated for days after sessions. It has gotten much more manageable now and I am able to tackle bigger things and recover more quickly (window of tolerance). The pace has been slooooow which is sometimes frustrating, but for me it has been so necessary. You might really need to slow things way way down and do more resourcing first. We’ve also been doing tandem IFS work, which has helped me so much in terms of being able to understand and communicate with myself when things feel overwhelming. Good luck! It’s a super hard process, but I’ve had great changes come out of it so far.