My guess would be a lab/staffordshire terrier mix, or a lab/shar pei mix. Since shar peis don't care much for other dogs, I bet it's a staffy. :) Good looking dog! ... View related article.
I'm going to assume that you inherited/rescued this dog - and I applaud your efforts! First of all, I would STRONGLY suggest investing in an appropriate size of dog crate for it, if you haven't gotten one already. A lot of times, half the separation anxiety is due to feeling vulnerable without their pack/person (also, if they're destructive in their anxiety, this will help protect your belongings!).
It will also help establish a 'going away' routine - the dog won't worry if you're going to leave them at any given moment, they'll know the signals for when it's time. I don't know if it necessarily helps, but I make sure to say goodbye and 'I'll be back!' before I leave. Dogs are pretty smart, after all. :)
Another thing you can do to ease your dog's anxiety is establish a very stable schedule. This helps the dog to learn that you WILL come back, and can expect you. I've found feeding the dog in their kennel at mealtime helps build a positive association with the kennel. I also give my dog treats when I put him in to reinforce that.
It won't be fast, and it won't be easy to listen to, but it WILL go away if you are gentle, calm and consistent. ... View related article.
I also advocate the yelping and turning away from them when you get bitten - but I would even go so far as to yelp when their teeth contact your skin. I grew up with malamutes and huskies, and my dad had a really strict NO TEETH rule for them, since they were big enough to take our hands off. That way, they didn't even try to test a gentle bite and risk underestimating their power.
If they're growling at you, then they're challenging your authority, and that's a MAJOR no no. When they're being snappy and wild, calmly flip them onto their backs and hold them down until they give up! You don't have to hurt them, but laying them on their back forces them to assume the 'submissive' pose. Sometimes you may have to do this for quite a while (my sister-in-law has a Jack Russell Terrier whose record is twenty minutes!), but they're learning that not only are you strong enough to be the boss, but you're patient enough, too.
