I need help on my writing...

I really want to be a writer... but i dont think im good enough.. would anyone please care to give me consturctive criticism??

Anyway, my problem is that my writing seems broken.. you know jumps from one topic to another topic.. like this...

"The deadline drew near and still no stories. How culd she possibly write with her schedule so cramped with homeworks, projects, quizzes and worst of all, exam is just around the corner. She mean, how could they expect so much of her when she can only do so little? A soft sigh escapes her lips as she ascended the stairs to her room."

See? what i mean? please.. i need your help. i need to write a story for a submission next week.. please.. i need your feedback. contructive criticisms pleasE?