I had developed moderately severe depression while I was using hormonal contraceptives.  I was approaching the point of actually seeking treatment, but I decided to try going birth control pill free first, as depression is a known side effect.  It worked phenomenally!  I have been pill free for over three months now, and for the most part I've been feeling great!  However, the mild anxiety I was experiencing prior to quitting has not completely disappeared.  In fact, it's significantly worse at times.  
My first two months off the pill  I had what I would call moderately severe anxiety attacks.  I was completely befuddled at first, but learned pretty quickly a few tricks that helped me cope and calm down more rapidly.  In month three, things started to dramatically improve as far as my anxiety goes.  I haven't had any attacks at all this month, and only some brief anxiety when presented with tasks that tend to trigger anxiety for me.  
I had been doing so much better, until today.  Boom!  Out of nowhere, an attack.  It's much less severe that what I had been experiencing, but it really threw me for a loop because I had been doing so well.  It's especially frustrating because I can't for the life of me figure out anything at all that seems to trigger it, especially this particular instance.  
But I guess I'll just have to take comfort for now in the fact that things are still improving.  I haven't felt depressed at all this month, so anxiety or no, that's a huge positive step!  :)  Things are looking up, and I actually feel like I'm good at something again.  I'm actually enjoying science again.  I actually feel like there's a possibility I can succeed.