Hello, I would be happy to help you with your question.
test will turn positive about 2-3 weeks after conception, so if you have not had sex for 4 weeks, then you are not pregnant with two negative tests. Second, low potassium is a potentially life-threatening problem, so if this has been a problem before and you are now symptomatic, then this needs to be checked immediately. You should also inquire about having your thyroid
I hope that this helps and good luck!