‼️How Accurate Is Eve?‼️

Okay, so I had my period on January from the 6th to the 10th and 6 days ago eve told me my period was about to come again on the 29th , but it never did and still hasn't. So here I am freaking out because, maybe I'm pregnant but it also says I have a period coming on Feb 21st, making me think it isn't late like eve is telling me because you only have one period a month right? eve is usually pretty accurate at the most a week off, and it's been a week.. someone please give ya girl some advice. Thank you.