my therapist and I talked about a reason why I sometimes can't start doing my work. I will allot time to complete tasks, I make lists, prepare coffee or snacks, whatever I need to feel like I can get my work done and then I sit down to do it and just can't. It's the most frustrating thing. 

She was telling me that my brain knows that i have all these things to do and that they might be challenging, so it just shuts off with that anticipated anxiety. I don't really know how to fix it. She's said to look at things in smaller, more doable sections, but that still doesn't help because I know I need to do more things. 

It causes so much procrastination and frustration toward myself. 

Does this happen to anyone else and if so do you have ways to help prevent it from happening?