Had sex a week after my last period, and a week before this one was due. i'm now 7 days late. 5 negative test. stomach pain. what's going on?

Repeat test: If you did the test correctly and it was negative at 7 days after missed period, you are unlikely to be pregnant. repeat the test 4-5 days later unless you get a period by then. Use first morning urine and follow the instructions for the test carefully. If you do not wish to be pregnant, use contraception all the time, every time. You may consider implanted contraceptive, or IUD. Practice safe sex. Get HPV vaccine.