In this case, you want to throw the baby out with the bathwater... that is, throw it away with the pot, medium and anything else disposable in the area. You'll then want to repeatedly clean the area with something that will kill all existing pests, and that will prevent them from coming back. That includes ALL plants in the grow area.
Have you been taking plants from outside and bringing them in at all? Do you go out and spend time in a garden outdoors, then go into your grow room without cleaning yourself properly (at least changing clothes and washing up well)?
You could choose to look at this loss positively... at least you haven't just finished spending half a year getting a perpetual running and completely dialed in, just to get an infestation that causes you to scrap the entire thing. Trust me, there's not much of a worse feeling than that.