I don't know if you've gotten any useful answers yet. If you haven't, here are some suggestions. I'm in Canada, so some the drug names may be something else in Australia.
First thing...you absolutely will not be able to fully detox with your current work schedule. In the meantime, see if you can keep the usage down to just maintainance (just enough so you're not sick).
You need to get a few days off. As uncomfortable as it may be I suggest you get to an addiction center (methadone clinic maybe). I am NOT suggesting you begin methadone treatment. However, in my experience, the doctors are helpful in giving what you need to detox.
Medications that help make the withdrawal bearable:
1) Clonazepam. 2 x .5 mg @ bedtime for 5 days (will make you drowsy)
2) Clonidine. 0.1 mg up to 3x per day (will also make you drowsy...and I've never used more than 1 a day)
3) Immodium or some other anti-diarrhea meds (OTC is fine)
Talk to the doctors, of course...but the above meds have helped me a great deal.
You really should consider following up with councilling though too!