could I be pregnant

So I was supposed to start my period on wensday of this week it is now Saturday so I'm 4 days past of getting my period, but today I had a little bit of fluid and then it turned pink when I wiped when I went to the washroom? Is that implantation bleeding or my period ? Me and my husband are trying to conceive, but we have only been trying for a week ,(started trying last Saturday) we want a baby and are so excited, me more than him ATM, he he said he will be more excited when I'm actually pregnant haha :p