How long did you study for the OAT? And were you taking other classes/working a lot while you were studying for it? If you do decide to take it again, I would highly recommend dedicating as much time as possible to study for it. But also make sure you're not psyching yourself out mentally, take breaks to relax and exercise, otherwise you'll wear yourself out before the test date. A huge component of standardized tests is mental, at least for me anyways.
Also, did you just go over the material once? I found that I reviewed it all a couple times (for the concepts I most struggled with) and that really helped solidify everything. And realistically, I'm assuming that's a study habit that will only help in optometry school because you learn an insane amount of difficult material.
I used the Kaplan OAT book and felt that it wasn't really missing anything in terms of what would be covered (it probably had way more than we actually needed to know). For any concepts that I felt I was struggling with, I supplemented with my old course notes and textbooks because the material in them was much more extensive and difficult (better over pre-prepared than under!). I also found that physics was also a section I struggled with quite a bit on the practice tests, and I felt like a huge component of that, for me, was time-crunch rather than the actual material. To overcome this, I tried to make sure that I REALLY understood the material (I used Khan academy on youtube for extra help understanding some of the concepts). Also, while you're studying, make a cheat sheet that has all of the formulas on one page and review that over and over and over, and make sure you understand the formulas, it makes it a lot easier to remember them for the actual test. And practice, practice, practice!
Also, maybe try shaking up the way you're studying? (ex. visual learning, writing out your own notes, etc)
If you do get an interview (either this cycle or next if you apply again), be prepared to answer questions related to the multiple OAT attempts and explain what you did differently. Good luck with everything, I hope works out! 🙂