Weird symptom

Hi! I recently found out I'm pregnant with our 2nd child.  I'm about 6 weeks along. Since almost the beginning, I've been getting these odd cold sensations mainly in my pelvic area and lower belly, almost as if someone was blowing cool air on me. It's freaking me out, and I can't find any accounts of people experiencing this. I've retaken pregnancy tests several times in a panic, and the 2nd line is as strong as ever. I did email my doctor's office and they didn't seem too concerned since I'm not in pain nor bleeding. They said I could come in if I wanted to, but they don't do ultrasounds until 8 weeks. Have any of you ever experienced anything like this?