Serious seperation anxiety

I'm at a loss of what to do about my female boxers seperation anxiety, I cannot leave her to roam the house because she will pee and poop everywhere (has done it in the past) and she is so anxious when we are gone she is biting the bars on her crate to the point her they are completely pressed together, she is also peeing in her crate often. I've tried the suggestions from my previous post such as give her something to chew, leave tv/radio on, excersise before leaving. She was not like this when we first brought her into our home (perhaps a little anxiety) she is getting worse and I have no idea why or how to make her feel at ease. Any suggestions besides what I've already tried?