Going crazy!!!

Stephanie • Tue, Dec 02 • First born arrived 4-9-17. It's a girl💗Baby boy arrived 9-8-18💙

Ok so I have been spotting for 13 days off and on. Nothing bright red just a little pink and mostly brown ( I know TMI). But this has never happened to me before. I don't understand what's going on. Has any one had this instead of a period? Took like hpt all neg. what could this be?