If your period came on time but you are having signs of pregnancy how long should you wait to take a home pregnancy test?

If you have your period, you shouldn't be pregnant. However, the pregnancy signs that you may be having could be signs of another problem. Or if you want to be pregnant, this can alter your way of thinking and make your brain and body do crazy things to believe that you are pregnant. You only have to be 4 weeks pregnant for the pregnancy test to show up positive.