Any idea where the bonus series is at? And do space missions/fps really give that much exp to gain about a level or two?

So I left Tatooine and went to Alderaan when I was able to, ever since Hoth, i've felt like i'm behind. I just finished Belsavis at 41, but it's recommended for 41-44. I'm not having a hard time or anything, being a sith assassin. Any ideas on how to "catch up" on the recommended levels for the planets. I don't want to finish the final planet and not be 50.

^ this