Late period -- Negative tests

Brittany
My period is now a week late. I usually have a 29 day cycle and today makes day 37. I've taken 2 tests and both have come out negative. I've had some days with increased cm then others when it's dry. I guess my question is, has anyone else gotten negatives on a test then end up pregnant? We've been trying for a little over a year & have had 1 miscarriage. Would really like our rainbow baby. 💗