Arrrrrgghh!! I learn today that I no longer have channels 30-70, and I don't understand why. I have digital cable, and a digital cable box! Why Comcast, why???

I thought I was covered, I understood that as long as I had digital cable, I don't need to do anything. I'm terrified now, with my desperately trying to save as much money as I possibly can, I'm going to have to get an additional box or something and be charged for it if I want to get the stations back. I'm not going to be able to do it! No more TLC, no more Travel or History channels, no more SciFi. No more CN!!!! I am sooooo mad!