Still trying to get things done

Basically, overwhelmed. I don't want to procrastinate, but simple arithmetic dictates that not every task can be completed to-day. The old way was to keep on saying that the less urgent tasks can be done to-morrow, but then to-morrow comes around, and those delayed tasks are just waiting to bite me. Now, I'm trying to juggle the many tasks which are trying to grab my attention - and somehow select the next task to be tackled on the basis of some sort of priority rating (or just to choose a task which can be done for the sake of doing it, and ticking off one item from the list).