16 weeks after unprotected sex , negative blood and urine test for pregnancy. doctors said normal discharge. 3 day period. light bleeding. prego ?

Unlikely: At 16 weeks a pregnancy test would definitely be positive and would be unnecessary since an exam would easily show a pregnancy and fetal heart tones would be audible with doppler.

Trust the Test: First, pregnancy tests are incredibly sensitive and it sounds like two different tests agreed, and were negative. If you visited a physician and they said it was normal discharge, that is the most informed opinion and the one I'd recommend you go with.