Totally totally. I have felt the same way. What has helped me was a few things:

1. writing 3 (max!) things I want to accomplish each day
2. writing down what things I learned each day
3. getting sleep! I know its hard haha. It's 4am for me and I have work tomorrow...
4. drinking water first thing in the morning
5. eating breakfast
6. exercising every other day
7. and this one is important: BEING OK with not getting everything accomplished! this is something you need to learn quickly. it is paradoxical but it actually helps you get more done

Definitely break things into small chunks and always pat yourself on the back when you make progress.

I'm not sure about the multi-tasking. It works for some and not others. Check out this blog by Cal Newport. You will find tons of good stuff on productivity there.