Hi Melisa,
Thank you for the blog entry, and to be sure: the Federal government is fair, honest and transparent in its hiring practices.
I'm sorry to hear that you've not met with the success you'd expected, I would counsel you to, as it relates to not being re-hired back into your old position, to contact that manager who indicated you were a valued asset.
And as it relates to whether you were qualified for positions you apply for, it is best to contact that Agency’s HR department to discuss your concerns, they'll be able to give you facts about how/if you qualify and they can possibly provide tips as to how you might improve your chances the next time you apply.
I certainly hope this helps.