Nipples swollen with white dots

If you are 4 weeks late on your period, and your cycle in the past has been regular, I would suggest going to a walk in clinic and having a urine sample tested by a professional.
Sometimes the at home tests show false negatives, as well as false positives. As for the nipples, it is quite common for nipple swelling anytime you are hormonal. Whether you are about to have your period, or may be pregnant the symptoms are very similar for both. The white spots are also nothing to be concerned about. Those are just Montgomery glands, or sebaceous glands, they just lubricate your nipple to keep it moist. These are also common on many woman. So do not feel like there is anything unusual going on, everything sounds normal for preparation for pregnancy, as well as hormonal changes before your period.

oh sorry the cramps are also mutual for both early pregnancy and obviously for your period. I felt many abdominal cramps when I was in the first weeks of pregnancy. Good luck whatever direction your body goes