Implantation bleeding

I was 9 days late for my period and assumed I was pregnant. I took a hpt 4 days after my missed period and it was negative. 6 days late I went to the doctor and urine test came up negative but I was told it was probably too early to show enough hcg levels. This morning I had red blood on my pj's and have been having light red/pink blood . Had a tampon in for 4 hours with only 1/4 saturated with light red mostly pink mucous like. I don't have cramps like with a period though. Is this implantation bleeding or my period? FYI I am usually like clockwork with expecting my period. I hope this means I'm pregnant! Any one else experience this?