Pregnancy

So I haven’t had my period all month. I usually start around the 4th or 5th every month and I haven’t had a period since last month. I took a pregnancy test on the 10th and it was negative. When should I retest? I have heart burn here and there & nauseous here and there too.. I already have a child. I just don’t know when to retest or should I just have a blood test done ?