Nauseous on "period" (withdrawal bleed). Second cycle of bcp. My blood hCG pregnancy tests are negative 6 weeks after last contact. Is this normal?

Likely normal. Bcp may be associated with nausea in some women. If these symptoms persist after a next couple of cycles, you may wish to discuss the option of trying a different formulation, with your doctor. If pregnancy test is negative six weeks after last contact, you are not pregnant.