Negative pregnancy test

Ok so, I stopped taking my birth control pills around January this year, had two periods in February, last one ending the 28th of that month. In March there were a couple times my boyfriend finished inside me. And I have not had a period this month at all. Is this my period trying to regulate itself? I’ve experienced nausea, slight headaches, and I’ve been extra tired. I took a test because I’m a week late but it was negative. Should I trust the negative test or try again in a couple weeks? Help. 😭