Hello im 35 missed three b.C. Pills begining of monty unprotected sex now missed period now brown discharge teo days negative pregnancy test?

Do a blood pg test. See your gyn , u need a blood pg test and other blood work, an exam and ultrasound.
Re do test. You may repeat the test in 4-5 days. Use first morning urine and follow the instructions for the test carefully.
Alternatively you could get a blood test for HCG level, now.