I took a morning after pill on 2/21 & started my period that day it lasted until 3/5 & now 3/17 i'm spotting what does this mean? could i be pregnant?

Probably not, but...: A morning-after pill can alter a cycle or two. Also, many women have occasional variation in their periods, some spotting between periods, a heavier or a lighter period, or even a missed period. Having one or two of these symptoms doesn’t necessarily mean there is a medical problem. One should check a home pregnancy test 3 weeks after taking a morning-after pill, to make sure the pill worked.