first of all, your therapist will absolutely understand that you were anxious and needed more time in order to navigate the situation...do not feel badly about it or beat yourself up...

on whether to email or wait for the next appt....if you feel like you are in acute crisis right now, need to talk about it, or else your well-being be in jeapordy, then e-mail her right now and spill it all out...she can not assess your level of distress and advise you properly if she does not know...

if you think you are ok until you see her, i would email anyway and just tell her that things were not ok this week and you really need to discuss that with her next sessions and wanted her to know so she could make it the subject of the next session, which will help you better, i think, cross that bridge with her next time

meanwhile, you could be jotting down your thoughts, feelings, impressions...i often make lil notes when i need to really target something in session, or i am struggling waiting to get there...

most importantly tho, don't do the guilt thing...life is hard enough on its own and this is YOUR therapy...not your therapist's..

good luck, hon