I would also wait around 3 weeks to do the test because i believe that if your having cramps ( no bleeding, or spotting, or a light period) you get when your pregnant any-way becasuse of the implantation, a tip- you should always wait untill 3-4weeks after sex untill you do a test
to avoid dissappointment and more of an accurate reading, OR wait untill you have missed a period, hope i have helped, just dont stress yourself of too much because that can make you not have a period, or being under