Wierd Database Thing

When checking my database I find a lot of members and posts missing. I hope someone can tell me what the deal is.
Even though people have been joining and posting right up until last Wednesday night when my host company decided to shut my site down because it was causing other sites to run slowly (whole nother story), when I check my database after migrating to a new host, my database only contains posts and members up until January of this year.
Anyone have any idea how this could be and moreover, what if anything I can do to get the rest of the posts and members back?
Even though people have been joining and posting right up until last Wednesday night when my host company decided to shut my site down because it was causing other sites to run slowly (whole nother story), when I check my database after migrating to a new host, my database only contains posts and members up until January of this year.
Anyone have any idea how this could be and moreover, what if anything I can do to get the rest of the posts and members back?