Im sorry you are having such a hard time...all I can say is you really have to concentrate on not drinking, are you strong enough to start a new job at the moment? You will surely lose it if they randomly test you. I have been through that and resigned in the end as I was getting tested and I couldnt stop drinking. If you are drinking your liver enzymes may be up, so just going a few days without alcohol wont do the trick. I have also taken antebuse and drank, dont do it, I was very ill...can you take some time off work to try and tackle your problems?
Keep posting and reading on here, it really did help to centre me when my thoughts turned to drink. You can do it, but you need time and a break to start to heal yourself. Take care x