First of all, you should undergo one blood test
for beta HCG along with USG lower abdomen to confirm/ exclude intrauterine pregnancy.
In exclusion of pregnancy, other reasons of delayed period are ovarian cyst
(most common), psychological factor, hormonal imbalance, stress/ anxiety, thyroid problem, wt gain/extreme loss, irregular eating habits etc.
Do some investigations to rule out underlying pathology like Thyroid profile & other hormone assay, blood sugar & prolactin
level etc. So consult with your gynecologist at the earliest and take suggestive measures.
Avoid stress/ anxiety by regular deep breathing or yoga, take healthy diet with iron supplements
, control body wt and maintain genital hygiene properly. Sore breast is due to progesterone
hormone. Wear tight breast support & take prime rose capsule to get some relief.
If you need further consultation with me, then you can visit http://www.healthcaremagic.com/doctors/dr-soumen-patra/63326.
Take care yourself.