If you are going to be around there today, I would go ahead and try another DE charge, and check it later for pressure and flow. If you still have decent flow, let it catch some more junk. Check on it again a little later and see. I'd try it if it were me. Either way, I would max out the filter on pressure and flow before I backwashed, DE charged or not. Dirtier sand filters catch more, so it's a balancing act between that, pressure and flow.