Hey Jonkst - try doing a search for MCAT correlation, there have been several threads on this topic that can answer your question 🙂
I scored fine on my practice tests too, and did one point better than my last Kaplan full length on the real thing.
The MCAT is about attitude too, you say that you are doing well now, so be cool, calm and collected on the big day and you should do just fine.
Good luck 😀