i actually just had eight sessions where i could go and talk. it sounds very undramatic, but essentially i hadn't really discussed it properly at all, so to just spill it all out all over the floor was like being hit by a train, emotionally. and just gave me permission to acknowledge that what happened had affected me, rather than being all stiff upper lip and copey about it. and that that was actually ok. (we were moving abroad - it would have been more sessions but we fit in as many as we could in the time left)
and the therapist knew that what i really needed was just permission to be upset, i think. and i think because i wasn't suppressing it any more, it wasn't popping up in flashbacks and stuff, and my head wasn't so tied up with suppressing everything that i was able to get a bit more grip on reality.
the timing was triggered by the death of a fellow student - in itself upsetting, but not really triggering. but at his memorial service his mum described the birth and his early life in very emotional detail and it was like looking into a mirror. and that was pretty much game over. and of course i felt horribly guilty about allowing my own personal stuff to get mixed up with her grief etc.
it wasn't perfect - but there's still ongoing stuff that's tied up and knocks me for six occasionally (dd2 has cerebral palsy), so it was more about being able to get on, rather than a cure-all, but i know not to internalise it when it does now. we have ongoing legal stuff, so it's having to read the reports and legal stuff that affects me now.
dh still has no idea that i had counselling. he knows i'm less flaky, but no idea what he thinks the difference is!
so, it depends. but i knew that after each session i'd have a good hour before i had to face anyone. (tbh i needed it, as i left each session looking like a tear stained wreck. in fact sometimes sobbed all the way to the car). if you can work in a buffer so that you can get yourself together if you need to before you have to face questions from your mum, then i would keep the appointment. but do give yourself a bit of a buffer. i had no idea it would be quite so messy. i'm definitely not the crying/ dramatic type, which was half of the problem i suppose.
interestingly, it did make all sorts of links with my past that i hadn't spotted before, (not so much the actual birth, more how i'd coped with it) so in hindsight it taught me a lot about how i have always dealt with difficulties, and how i can better cope for the future.