Is it possible that I’m pregnant?

Hello ladies! Just a quick question. My period is delayed for 3 days now. I did a 2 pregnancy tests yesterday but one was negative and the other invalid cos I didn’t see any lines. There’s no spotting at all and my period comes regularly. Does this mean I could still be pregnant despite the negative PT results? 🤔 cos me and my fiancé are trying to have a baby.