I'm sorry to hear you are struggling so much right now. I'm glad you were able to reach out to your pdoc. Any chance you can get in to see your therapist asap?
My phone doesn't like to post links, but you can search pc for their into on self injury. You can also check out selfinjury.com for info.
People self harm for many reasons. I think you may be on to something with the Mine of thinking that you are turning your frustrations onto yourself. Sometimes we don't know what else to do, or another way to get the frustration out, so we turn it into ourselves. My reasons are too many to list, but the biggest one is relief from intense and uncomfortable emotions. I would say your situation at work is quite tense and uncomfortable...