Hi Emma,
If you do not feel like you are ready for the exam in two weeks and if you are not close to the score that you know you need, then you probably should push back your test date. Since the July and September exams are both equally good options for applying this year, there is no advantage to taking the June exam date before you are ready.
More importantly, if you find that your score has decreased, make sure that you are actively analyzing the changes in your performance. It is unlikely that you have gotten less intelligent since starting the course, but if you are only looking at the final score out of 180, that's how it can feel. Instead take a look at your progress on specific sections and concepts in the exam. If you took more than a handful of tests before starting the course, you should be able to compare your results, and find what strategies have not worked for you yet.
Taking the LSAT course, especially for people who have studied previously on their own or have used different approaches, can be jarring. Since we throw so many concepts at you in the LSAT course, it can be hard to adjust what your approach to the exam. Ironically, people who are completely unprepared for the course generally have a slightly easier time in this one regard. Since the test is so long and so dense, it's easy to get overwhelmed if you try to do too much at once. Many of my students who come to us after trying a different test strategy encounter this difficulty. I don't want to assume that this is what's happening to you, but it is not an uncommon phenomenon.
Let us know if there are any other issues you would like to discuss. And finally, here is some more reading that I think may help you out:
LR score is tanking
Pushback Test Date Again?
The Benefits of Failure
My LSAT Score Just Dropped. Now What?
