I caught it when 25 weeks pregnant.
Ended up on oxygen in A&E within 6 hours of the first blister appearing as a result. Nobody from Maternity would come to check whether the baby was OK because of the fear of taking the infection back to the wards. So I spent the time pushed away in the furthest corner of A&E until my sats came up a bit. The only interaction I had was somebody looking in through the curtain to check I was still alive every few hours. No food, no water, nothing past the first person who saw me who stayed past his end of shift, saying he'd already had it, so was prepared to put the mask on me and one nurse calling through the curtain to let them know if I go into labour.
I had them everywhere - inside and out - for weeks. Vaginal chickenpox is not something I'd wish upon my worst enemy. Had it been any later in my pregnancy, DD could have suffered horrendous effects (including blindness) and, any earlier, I could have miscarried.
My entire body felt like it was on fire. I've had severe sunburn before and that was a walk in the park in comparison. I've spilled boiling water over myself and that was nothing compared to the pain of chickenpox.
Calamine lotion burned and stung. Water burned and stung. Clothes burned and stung. Breathing burned. I lost over a stone and became anaemic when I'd previously been fine - but I couldn't be checked/have a blood test until I was clear of the blisters, as the GPs wouldn't have me in the surgery when they had immunosupressed and/or elderly patients there and their HCA hadn't had it.
Had I not caught it then, but did when I'd started medication for Psoriatic Arthritis, I'm told that it can easily become fatal (which is why I suppose I was barred from the GP and Maternity/Antenatal unit for the duration).
Vaccination is worth every penny, IMO.