Awful leg pain

I'm almost 9 weeks pregnant and recently I've been having the God awful pain in the back of my leg, like so bad I can't walk! The other day it came on out of nowhere and I collapsed in the middle of meijer (how  embrassing) I read about sciatica and it kinda sounds like that could be it.. But this has NEVER happened before in my life! Can sciatica be triggered from pregnancy? I have an OB appt on Tuesday and I plan on bringing it up to him. But I'm just curious! I'm totally nervous about leaving anyone espicially now that it's getting icy! All I need is a bad leg and to slip on ice. Ughh!