Pink?

Ok I took a test 3 days ago said neg so I resided to wait till after tomorrow to test again that will be the end of the 28 days today I went to the bathroom and had a pink discharge on the tp but when I went a hour ago nothing at all this is new I have had 3 kids and this is a first time I have been late then a neg test now the pink could it be ib or me about to start help!!! Worried about this