Ok I'm 17 and I'll be 18 in less than a month, and I've been with my boyfriend for a year. the thing is my last period was march 15. I had protected sex. I used a condom and am currently on the shot, but I had sex the first week I had the shot which is considered unsafe without a condom. So I'm late and I took a home pregnancy test last week which came up negative. But I'm still concerned because I still don't have my period. I was wondering if the shot could prolong your period or if I should just buy another test. thankyou for any responses!!!!!!