Cycle usually 28days af was due mar 8. i had all pregnant symptoms. hpt was neg mar 10. spotted pink 14 &15, 16, 17 spot black. could i still be pregnant?

Unlikely: If your pregnancy test on march 10th was negative then likely you aren't pregnant. Especially considering that you've been bleeding/spotting the 14-17th. If you're worried, however, you can always take another pregnancy test to confirm. See doctor if irregularity continues, can be sign of fibroid, polyp, thyroid irregularity, weight (thin/heavy) or hormone imbalance or endometriosis. Best of luc.