If you have missed your periods by 5 days now and the pregnancy tests are negative , it is unlikely that you should be pregnant . However the sensitivity of urine pregnancy test is best after 7 days postalised period , so it is suggested that another test may be performed on the 8th post missed period date and if negative again, then pregnancy is ruled out. The symptoms you are experiencing in form of sore breasts, mild cramps and tiredness , in absence of pregnancy can be attributed to PMS symptoms and indicate that menses shall ensue in next few days.
I hope i have answered your query in detail,
wishing you good health,
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