I get triggered a lot. I also have trouble reaching out, but I've gotten a bit better about it. I don't reach out in the moment, but I will call t after, or write to her to take to next session so we can talk about it. She's helping me see what parts are flashbacks, and how to identify them so I can move through them easier. It's definitely a long process, but we're getting somewhere. I have a similar fear reaction to the thought of contacting t (or anyone really) when I'm triggered. We've figured out is linked very much to the past, so I try to keep reminding myself it's ok to reach out even if I'm scared.
I'm glad you will be seeing t soon. Hope that goes well and you can talk to her about this. Maybe you guys can come up with a plan in case it happens again.