Odds of pregnancy

What are the odds of being pregnant? af had arrived 4 days earlier not as heavy as my usual af but still enough to have to wear a pad or tampon that lasted for 4 days but non of my usual af signs came with it and bleeding was different it was fresh looking blood (red) then when the bleeding stoped I was having my normal af symptoms for the days I would of been on. Took a pregnancy test on Monday and it was negative. I just feel a little odd (like I have done with my previous pregnancys) anyone experience anything like this or similar Tia.