How long could implantation bleeding last?

So last week u was bleeding from Tuesdays until Thursday it was really light bleeding but it happened the exact day that I was suppose to get my period. Usually my period is a little heavier and last until Saturday morning. I just brushed it off as if it was my period but since Sunday I've been extra emotional and have been nauseous everytime I eat. I can't finish a meal without having the feeling that I'm going to vomit or pass out. I did mess up my birth control last month around the time I was ovulating I missed it 1 day so the next day I had to double up and then I did the same thing a few days later but I did make sure I still took my pill. I'm not sure if doing that could of mesed up my pills but I'm a little nervous