The futility in it all

Why do i feel like everything i do here is just in futility? I feel like nothing is ever good enough, that even though i study for 6-7 hours a day, i am getting no where. I now have to worry about all my classes being c's instead of a's like i was shooting for and i feel like there is nothing i can do to stop this situation from arsing. The anxiety rises more and more every day as i take quiz after quiz, test after test, with bad results, or worse results than i really wanted. I just don't know what to do anymore. This blog is the only thing i seem to be able to do well, this and explaining things to people that I'm studying. But i can explain away all day, but if i don't get the answer right on the tests and answer how my professors want me to then its all for futility. I just don't understand what I'm doing wrong anymore. I just don't! I was an amazing student in high school, almost straight a's the whole way through with a few classes here and there that weren't a's. Then i went to community college and still did amazing! Got on the deans list 2 semesters in a row! Now how is it that i come here to GCC and I do the same tactics that i did before that worked, and they are failing me miserably? I am getting tutoring, i am talking to teachers, i am studying like i should (least how i think i should), and it just ISN'T working! I don't understand it! Honestly at this point if i get b's in everything and a C in Ochem ill be the happiest person alive! I dont even care anymore if other's will be disappointed, ill make up for the qpa in the next few semesters, just PLEASE God! I need b's! I NEED b's! I don't know what else to do but the beg and plead! I am even getting points back from teachers and doing all the extra credit, doing study group sessions, and not going to a lot of my extra curricular activities! Nothing is working and i don't know why and I'm just about ready to give up! I feel like I'm going to explode all the time, i am never peaceful, and i always have too much work to catch up on, even when I'm ahead of schedule. I just cant life today! I don't know what else i can do anymore. This just isn't working! I want to be a Vet with every fiber of my being and i want to achieve and do the great things that you have called me for God, but how can i do that when i cant figure out what I'm doing wrong?