Ttc. usual 50 day period a day late. neg. test. but some lower cramps and low back pain. sore breasts. could i still be pregnant or something else?

Tests are accurate: Today's home pregnancy tests are very accurate and not affected by foods, herbs, common illnesses, sexually transmitted diseases, vaginal spotting, or medications. A test gives a reliable result 3 weeks after sex (or when conception might have happened) or 1 week after missing a period. If done sooner, a negative result may be due to testing too early, such as less than 2 weeks after conception.