I haven't started studying for the MCAT yet, but regarding your score of 17 at Kaplan.... A friend told me that Kaplan's MCAT is harder than the real one and you shouldn't get too concerned about this score. Try AMCAS practice MCATs and see how much you get.
Although taking harder tests in the future may actually prepare you better.
This
👍. Kaplan tests are harder in terms of being more confusing but having straight forward answers. They do however have much better curves than the real MCAT. The exception to this is the Kaplan Diagnostic, which is both incredibly difficult AND has a horrendous curve. This is probably so they can make there score guarantee (ensure everyone has a low diagnostic score so that they can do better on the real thing).
To answer the OPs question, it sounds like you aren't doing enough studying and aren't following through with practice tests. I'm not sure when your scheduled test date is, but if its April or May I would suggest doing a practice test once a week until your actual test date. I know you aren't fully done with a review yet, but these practice tests are essential for both your review and developing of test taking strategies. Until you finish your review completely, don't care what you get for scores. Instead, use them to develop your critical thinking/test your knowledge up to this point.
If you are taking the Kaplan course, you have access to both the Kaplan tests and the AAMC full-lengths. The total of these gives you something like 18+ tests if I remember correctly. I would start with the Kaplan tests and then move on the AAMCs when you are completely done with your initial review of the material.
I would also keep a log of all missed questions that you get wrong on the tests. When you finish a test, the most important thing to do is GO OVER EVERY QUESTION WHETHER YOU MISSED IT OR NOT. This is crucial! You need to see why you chose the answer you chose for each question. If you guessed on something, you need to know why you had to guess on it. If you got it wrong, you need to see what error in logic/understanding caused this to happen. If you do this for every question, you will start to see improvements very quickly.
Keeping a log of all questions missed indicating the section, question, topic, an explanation of why you missed it will be invaluable for your review. As you finish all of your Kaplan books and start taking tests, you'll need to start seeing where your weak areas are and these question logs can really help pinpoint your problem topics.
Also consider purchasing the ExamKracker series. They do a great job of presenting all of the topics covered on the MCAT in a concise manner and really help hone your critical thinking skills. They also have a great verbal strategy that trumps the other test companies. EK Verbal 101 is considered by most people on this forum to be the best preparation for the Verbal section on the MCAT, so definitely keep that in mind going forward.
Anyways, I hope this information helps you out. I know its a ton to take in at once. Good luck, good studying and I hope to see you posting in the 36++ MCAT study habits thread!