I leave all my beers in primary for at least 3 weeks. I have had a couple of my 18 brews still have some left over krausen or yeast rafts when I bottled. I would not worry about it unless it was still an active krausen after more than 2 weeks. Even then if the gravity was as expected and stable I would probably rack out from under it.
What's your current gravity? Krausen/foam really can be misleading. I have used bottle harvested hoegaarden yeast that had had a krausen on it for upwards of 3 weeks, where even the gravity reading showed that the beer was finished.
Big time noob here but NB slobber was my first batch (in secodary bout to bottle this weekend) and it took 12 days for it to drop checked all might google and most had similar experiences!!!