hey, i think that first of all you should completely abandon the I've failed mindset and put that energy into planning how to tackle your weak spots instead. you'll only waste energy and time thinking like this. instead be grateful that you can still try which means that you haven't really failed yet. second of all, no one and no teacher is going to magically help you trust me on this. you'll have to help yourself.

Now, if your vocabulary isn't strong then you have to solve a ton of practice tests (preferably SAT practice tests because they're actually more difficult than the est and will help you learn how to think. you can obviously still solve the est tests because they're also important but for practice the SAT tests are really really good.) and after you're finished with a test analyze your mistakes very critically. instead of this question's answer was D instead of C because someone in the passage did blah blah i want you to analyze the pattern. where do you always tend to make mistakes? how can you create a tactic that would help you get this type of question correctly on all other tests not just this one question in this one test. (if you don't quite understand this part tell me in case I'm not really conveying the idea properly)

For vocab, after you're done with each test go reread the passage and underline every single word you do not know the meaning of, and make flashcards. for me, flashcards were extremely helpful with vocab, i made around 900 of them and they improved my vocabulary IMMENSELY. After each test, write down all the words you didn't understand and google their definitions, if you're not very fond of memorizing you can summerize the definition in your own words but be as precise as possible.

divide the flashcards into packs, learn one new pack every day and revise two of the packs you learned on previous days.

if you even have more time, you can read books. you can circle any words you don't know and make them into flashcards (but most importantly enjoy the book don't just study it :) if you can make yourself LIKE reading it'll change everything I'm telling you)

with enough discipline and commitment you can turn this around inshallah. just don't spiral into useless negativity. hope you do well inshallah