many prep company's scores are not a true reflection of what you'd expect to get on D-day. as Jivana just mentioned, kaplan is one of them. you should use their tests as practice, not as a predictor of your score.
i had a similar experience with
manhattan gmat. i scored 70 points lower on one of my
MGMAT tests than i did on my GMAT Preptest. luckily, people on the forum assured me that the best indicator continues to be the GMAT Preptest. I didn't let that low score get to me, and neither should you.