That depends on when you took the test. If you took the test while you were still bleeding or just shortly after, then it's possible that you tested too early and that what you experienced was actually implantation bleeding. A good way to tell the difference between implantation bleeding and a light or wonky period is A) How heavy the bleeding is (heavy bleeding with clots is not implantation bleeding) and B) How long the bleeding lasts. Typically, implantation bleeding is only going to last a day or two. Anything more is likely a period.
If you tested at least four days after the bleeding ended and your test was still negative then you're probably not pregnant.