Confused and Need Some Advice

I have been studying diligently, and my PTs have been around 165-170. My June LSAT was 162, so I was hoping in August, I'd get something above what I got in June, but when I checked the score, I received a 155. In June, I left the test center feeling bad, running out of time, forfeiting some questions. In August, I had some time left (Like 2 min) for most of the sections. I felt good about moving on with some questions and double checking the ones that I wasn't sure of. I have no idea what went wrong and I feel like the months of studying between June and August (in which I thought I made progress) just went down the drain. 155 is only 3 points away from the first ever diagnostic LSAT test I ever took in April. How did this happen, and what can I do to fix this?