NEED ADVICE: af a whole week late

so AF is officially a week late. I was supposed to start on the 4th. last month a different app predicted my period exactly right to the exact day. but this month its a whole week late?? got a little emotional earlier this month thought it might be PMS so I checked to see when I was supposed to start but I was already 2 days late. just took a hpt and got a negative but it also wasn't with morning urine, this app though says I'm supposed to start tomorrow but this one has always been kinda off for me??? should I just test again in the morning if AF doesn't show??