False negatives?

Although every test I’ve taken has been negative I still think I could be pregnant. I have been absolutely restless these last few nights, my boobs are sore, and I wake up feeling nauseous but never actually vomit. My period is 20 days late and I have been trying to conceive on my fertile days. I have took 4 test, one at 5 days late, one at 11 days late, another at 18 days late and one this morning, All negative. My mother didn’t get a positive with my brother till almost 3 months into her pregnancy. She keeps telling me to go get a blood test but I don’t want to walk in there and then it be negative to because I will just look like an idiot. What do you think? Forgot to mention that I used to have really irregular periods and that is why I am so hesitant to go to the dr. My period had been regular for over a year now though.