Pregnant?

So, we aren’t exactly trying for a baby, in fact, he is pulling out. It looks like my ovulation was this week from my calendar. I’m breastfeeding so I’m not even sure if that is accurate! But, I woke up with bad heartburn after eating spaghetti tonight- which never happens to me unless I’m pregnant. It’s been a week since we had sex. Could this be an early pregnancy sign? I know it’s insanely early.