How long do I wait?

How long after unprotected sex can you take a pregnancy test? It's been 11 days, I've read that you have to wait 2 weeks for accurate results. At 10 days I had what looks like implantation bleeding and a couple cramps but not like period cramps.i think I'm pregnant but the dollar store test said negative..should I get a different test and try again at 2 weeks?