How can I deal with all the things I need to get done?

Make a list. Make a list and prioritize. Understand that you may not be able to accomplish it all. Never be afraid to ask for help. Lastly, don't bite off more than you can chew - learn to say no on occasion.
Read David Allen. David allen has a book on clearing clutter both mental and material which i find has clear directions - he says split task to immediate, short term and long term and work towards them.
1 thing @ a time. Set a goal to do 1 thing @ a time and strive to finish the set task until you move on to another. If you pick up many tasks at once, chances are you will get frustrated with your failures before too long and will have to start all over again.