Trub is a general term for sediment in the world of brewing and homebrewing. Trub happens to everyone, so you might as well get used to it. It’s a collection of hop sediment, hot break, cold break, dormant yeast, and proteins that have settled to the bottom of your carboy or fermenting bucket after active fermentation. If you’re clever enough, you can actually harvest beer yeast from your trub and use it for a few generations.
I always perform a two-stage fermentation on all my beers. Transferring your beer from a primary fermentor to a secondary fermentor will result in cleaner beer and minimize the chances of generating off-flavors in your finished product. It’s a bit of a hassle, but it’s well worth the payoff in the end.