$1 test

Okay so for some days now i’ve been getting really bad period cramps. But im 6 days late, so i decided to take a $1 test and in less than a minute these two red lines came up. But my bf said since it’s cheap it might not be accurate. are period like cramps normal in early pregnancy ?. i might be 3-4 weeks pregnant. and also, should i go buy a more expensive test??