Month late negative test

Tabi
My last cycle was February 10th and have not had any bleeding at all. I went to the doctor on the 25tb of March negative urine and blood test. They sent me for an ultrasound to check for cysts and I have no cysts. Now I am a month late and still no AF. I took a test a couple days ago and it was negative. This is frustrating!! Anyone have this problem before