Not worried but wondering

Well my bf and I only had sex once this month, which was the 1st (happens to also be the first day of my fertile window) Lately I have had heartburn and lower abdominal pressure. I went the the ER because it got bad but they told me to see a gastrontologist because the pregnancy test came back negative. My mom told them that all her urine pregnancy tests came back neg. and had her "period" when she was pregnant with all 5 of my sisters (including me). They did not believe her and only did a urine test. Could I be pregnant? I highly doubt it because I have been having severe ovarian cysts, but it is always a posibility, right?