welcome to healthcare magic. since you say your periods are always on time within 26-27 days and this time you have missed your period, you should get a blood test serum beta hcg
done which will tell you if you are pregnant or not. once that is confirmed then your other problems can be addressed. the breast pains are due to hormonal
changes, get an examinatio done by a doctor to rule out any lump/mass. best of luck.