Sounds fairly normal. Sorry if I missed it somewhere, but is this stuff you have already shared with your therapist? It might be that sharing a lot in your diary here made too much "real" without time to process. I think that can happen easily, and actually why I personally avoid writing much about my trauma, unless e-mailing my therapist and knowing she will respond.
I'm also coming from the point of view of an under-sharer, though I have had those moments of feeling exposed and how fragile it makes one feel...so I do understand that. What helps me in those times is getting a grasp on anything very familiar and cozy...walking my dog, for example. Anything to ground, even just washing the dishes and taking care of the little tasks that keep me grounded in the little daily things. Whatever keeps me present.
But from the under-sharing perspective, I think it's helpful to point out to any readers who relate that simply sharing doesn't heal everything (and I do relate too, even as someone who generally under-shares, even in therapy). For example, I do not have good memories of my worst traumas because I was 1. too young, 2. unconscious (ICU on life supports or just super drunk), and 3. likely dissociative during some interpersonal traumas. I don't actually have a whole lot I can talk about. If I'm talking about the parts I remember, it is still very difficult. But it helps me to know that I can heal even without being able to verbalize all of it (that would sort of be another post about regulation and body-level stuff, so I'll move along here...).
It's really helpful to share in order to organize our reality and also have validation. So good work...but also good work recognizing your limits. That in itself is a huge part of recovery. Take your time. If it seems helpful to go through stuff in therapy pretty well first, then use your diary to put it into writing or process a little further, maybe that will help. I really understand writing as an important tool. I seem to make more sense to myself through writing (I'm lucky my therapist accepts e-mail because I've shared a lot with her that way, and just the writing process helped me reframe or organize some parts of my story). You're learning a lot about yourself and how you can heal, and that's really huge. So keep noticing what helps and what doesn't help. It's no perfect journey, but most important that you are trying and challenging yourself here and there! I'm a little late on this post, so hope you are feeling a little more grounded today. Sounds like you're doing lots of good work!