I don't know if I can do this

Every year we have to do a self-review as part of our performance review. I know it's coming every year, yet every year I get stressed out by it. We received our form late last Friday. I've looked at it every single day this week and didn't write anything down until yesterday. The questions are: Goals from last year and how well you completed them, Accomplishments, Strengths, and Weaknesses. I made myself a list of all the tasks I've completed, but they hardly seem like anything worth writing as an accomplishment. I know when I get in the actual review, my boss will ask "do you really believe BLAH???" I honestly don't feel confident enough in any of the things I'm going to write to defend them. I feel so negative right now that I'm not really sure I deserve a raise, although I know I worked pretty hard and I really WANT a raise. By this time next year, I'm hoping to have a baby and I know it will take money to raise one! But it's so hard for me to justify...whenever I look back at things that happened, I see the mistakes I made, not the good outcomes. But I still can't list my weaknesses...and can't come up with any strengths. I have to turn it in by the end of the day and just don't feel like I can. I thought I'd be in a good enough mood at some point this week to be able to do it, but I haven't been. And here it is, Friday.