Ugh help please!

Im 15 weeks 2 days. The past 2-3 days I've been having continuous sharp pains in my lower stomach. At first they were on and off but today it's been a constant pain. Yesterday my stomach got rock hard when this was happening. It's so uncomfortable. Is this typically normal? Or should I be worried? I had an appointment on Thursday and mentioned it to the nurse and she said its normal. Nothing else was said about it.