Period late 4 days neg test spotting m-t on off very little starts pink then if i use tampon it comes out brown and sticky like. what's happening?

Brown = old blood: Irregular periods are one of the most common problems obgyns treat. If this is one time problem it usually resolves on its own. If this is a recurring problem you should be evaluated. Infections & hormonal changes can cause spotting. There are many options available to help regulate the menstrual cycle. Schedule a visit. Your pregnancy test is negative indicating you are not pregnant