The physical part of your sitch, that is all the justification you need girl. No excuse, ever, don't care what chemicals are in the body!
The shame and anger will subside in due time. Of course most of it can be attributed to natural defense mechanisms. You get bit by a dog, you tend not to like that dog as much as you did before and you might even be a bit more cautious around all dogs. Just don't let it consume you. Doesn't sound like it is, but just be conscious of it.
As good as I'm feeling these days, I still get a "tweak" every now and then! The remarkable thing is how quickly it passes now! Minutes or seconds instead of hours or days.
