according to your description,
ovulation has occurred.
normally when ovulation occurs either menstruation
should start within 12 to 16 days or pregnancy
has to be there.
But there are exceptions to this also.
Now if we consider the normal things there is a chance of pregnancy. But as even on 45th day your urine pregnancy test is negative, you better to go for transvaginal ultrasound
which will rule out presence or absence of pregnancy.
depending on the result you can take further treatment.