Stomach pains

I have had pretty severe, high stomach (right under my breasts) pain in the middle of the night twice. I didn't know what to do, so since it was high, I thought it might be my stomach so I took some tums and laid in a hot bath. Eventually it went away, but was pretty strong for a good 30 minutes. I'll be 12 weeks tomorrow and I'm beginning to wonder what it could be. I don't see my doctor for another 2 weeks. Any ideas? Anyone else experience something similar?