Spitting out blood after septoplasty?

13 days ago I had Septoplasty.I can breath much better now. What im worried about I'm still having dark red, really thick mucus (almost looks like membrane) coming through mouth every morning upon waking up. In the day time I'm spitting out small amounts of blood mixed with mucus almost every time I spit. Is that normal and if there is something I should do about that or it is something I should be worried about?