Negative on all the tests.

So the doctors confirmed it with my second round of blood work. My bf and I are TTC and we were so excited when the test came back positive. However after 2 rounds of blood work there was nothing. I now am 7 days late and have a doctors apt at 9am tomorrow to make sure everything is ok. They sounded worried with my results so we shall see what is going on. My period has never been late! Only when I am pregnant. I am scared something is wrong. And I have been reading and I’m freaking myself out. I just want to know what’s wrong with me 😭😭😭