Fear in failing? (algerbra 1)?

why do i feel like i will fail algebra 1 this year i am a freshman and i am on my final 9 weeks and i feel like i will fail my first nine weeks was a 71 2nd was a 72 and third was a 72 and my midterm (10 % of 1st and 2nd semesters) was a 67... i never did homework but 4 times in these nine weeks (none in first) (3 in 2nd nine weeks) and 1 in 3rd nine weeks) THIS 4th nine weeks i will be doing ALL of it!! and this semester the learning are the most easy then all the others (strange huh?) i want to have atleast a 75 on progress report! but he is BEYOND CARELESS when he grades I FEEL CHEATED AS F***! this girl she makes mid 80's but on here mid term she had a 38 and missed most her questions and i seen her paper BUT on her next report card he put an 88!! WTF!?!? how careless!!!!!! it just infuriated me when i saw that... but i don't complain in school ever because i dont like stiring up stuff..