First of all, 1-7 days alteration of period date is normal thing. Therefore, I suggest you to wait at least 7 days for period and if you do not get it, you should repeat the home pregnancy
test again or blood test
for beta-HCG. Early pregnancy test is nothing significant.
Cervical mucus discharge may be seen prior to commence of period or early week of pregnancy. Maintenance of genital hygiene is the key thing. Sore breast is due to progesterone
hormone. Wear tight breast support to get some comfort.
In case of negative pregnancy test, you may need to proceed some other investigation like USG lower abdomen, thyroid
profile and other hormone assay to rule out underlying pathology.
Avoid stress, take healthy diet with Vit-E & Folic acid
supplements, control body wt and take a sound sleep.
Be well and take care.