Pregnant Or Delayed?

Ask ko lng if may mga mommies na same experience sakin. It has been 8mos since I gave birth to my child via Emergency CS. Since then, full breastfeed ang baby ko. I've never taken any birth control pills before, and active kami ni hubby. Though withdrawal and calendar method naman, and yes aware naman ako it's not 100% reliable. And yes, delayed na ko ngayon. My first day of mens was last month June 14 and ended on June 17, till now wala pa kong mens. I already took a pt yesterday and it was negative. But still, wala pa kong mens till now. I'm asking if there's any mommies or Obs out there who may have the same experience and can tell me whether accurate na ba ung pt result. And if ever na buntis nga ako, is it safe? Hoping someone can advise anything. Thank you 😊