Brown spotting

I have had tiny bit bleeding but mostly brown spotting since Sunday so been like it four days nw sometimes it gets real thick and sometimes it's not much at all it's just like a brown discharge but I've never had this before I went to doctors but I started bleeding just before I went and she just said she's not worried then it totally stopped again just brown discharge and I've done two pregnancy test both negative so deffo not pregnant I didn't no weather to go back to dcs or just wait and see if I start properly am quite worried