False positive????

Myra • Female. 22. 🏵pro-choice🏵 pro love ❤️💛💚💙💜. Pro cats 😺😻😼😽
Okay so last night I took a pregnancy test. It was positive. So I went to Walmart and got another 2 tests. Took one last night and it was negative. Took one just now (just woke up) and it was also negative.... I've never been pregnant before. Why would I have a false positive????