Okay this thing is saying I am 4 weeks and 3 days pregnant but my at home pt says negative and I have missed my peropd... what is wrong?

What exactly is this 'thing'?

How old are you?

What exactly is this 'thing'?

Is this some Internet "thing" that told you that based on your last menstral period you'd be 4w3d since you're a few days late?

Trust the home pregnancy test and if you have doubt, call a doctor for a blood test.

Sometimes periods are just late - it happens to all of us at some point.