Really confused!

Hi everyone just needed some advice really, i’m now 6 days late and im never late... all of my tests are negative upto today. My doctor said i could have been pregnant and it didn’t work for whatever reason and to give it another 3 weeks to see what happens as it is still very early so might be?? Its so frustrating i just want to know. The only other thing is my boobs are killing me. They normally hurt before my monthly but not this much. Should i give up or keep testing??? Any advice i’d be grateful.