Worried..

Brittany
So I take beyaz and have been taking it continously since november.. at the end of january (the beginning of my new pack, 4th month) I started to spot...dark brown when I wipe. I ended up having sex on the 23rd, we also used spermicide and he pulled out..about 4 days later the spotting came back and within a week I was bleeding heavier for about 4 days..bright red fresh blood. I just took a test 18 days after(friday) and it was negative. These results should be pretty accurate right??