Staying motivated through impatience

I am looking for advice for a specific situation that I face regularly regarding time management. I am in school part-time taking several science prerequisite classes and science has never been my strength. I will soon be in school full-time to pursue a master’s degree in a health field. In order to get work and school done and still enjoy my free time, I have to get things done within a certain time frame.

I schedule my neuroanatomy reading to take me 4 hours and it takes me 7. I schedule my writing assignment to take me 1.5 hours, and it takes me up to 4 hours. I have heard the suggestion to do B- work, but I am required to maintain a B average for my program and I always aim for an A.

As soon as my timer rings to alert me of my half-time, I realize my work will take longer than I planned and I begin to feel extremely impatient and frustrated. I lose motivation and focus for the tedious subjects I am studying. I take a break to see if it will help, but this also prolongs the time that I set aside for my assignments. When I finish the assignment, I look at all the things I did not get done today and I start to feel even worse about my inability to progress quickly.

What do you recommend for me to handle the frustration that I feel when work assignments or school projects require twice the amount of time I planned for?

Thank you.