It sounds as if you have a cartridge filter. If that's the case, then you are correct, adding the DE, especially too much will clog and maybe harm the cartridges. Ben has written a great tutorial on how to clean a cartridge filter. Follow Ben's and Watermom's advice. Keep that pool shocked, and don't add any DE to your filter. ( If it is a cartridge type). Good luck, follow the directions of the moderators here, they have a ton of knowledge, you're in good hands.

Tom