I'm 17 days late with a lot of clear vaginal discharge but 3 negative home pregnancy test. could i be pregnant?

Unlikely: If you did the test correctly and it was negative at 17 days after the due date for a period, you are not pregnant. Menstrual irregularities are not uncommon and anovulatory cycle is a common cause. If you miss more than two periods it would be time to see your doctor. Consult this site for more information on this topic. http://www.nichd.nih.gov/health/topics/menstruation/conditioninfo/Pages/causes.aspx