I actually had to overcome the same problem, and I know exactly how frustrating it is.
What I find helpful is to really identity what's slowing me down during the timed section. By this I mean, take note of when I'm panicking and spinning my wheels…
I just scheduled mine, after seeing this post a minute ago. If you already have a Proctor U account, you can just go to their site and login. On the home page, it should lists any applicable tests, and to the right of the banner for "JUNE LSAT FLEX,…