Back Pain

Michelle • 4 kids, #5 due 8-25-15
So, I fell about a month ago while exiting a shopping mall (where, ironically, I just purchased a good pair of boots). It was almost blizzard like conditions and I landed on my booty/tail bone area but there was a thick layer of snow. It was a hard enough impact to make me pee myself, I was about 13 weeks at the time. 
Now my sciatica has been almost unbearable when I stand for too long or sit in certain positions. It also hurts at random times. I've never had any issues with my sciatic nerve in previous pregnancies. Do you think this could be a result of the fall (it mostly hurts to the left side where I landed) or probably just pregnancy induced? Should I talk to my dr about it? I walked to the store yesterday because it was nice out and I was out of commission the rest of the night. I could barely move and I'm only 18 weeks now.