Thanks for your reply and explaining it in detail. I was not aware of this fact that you are taking alcohol with Amitriptyline.
See, Alcohol is an CNS depressant and it is not at all recommended to take it with any other medicine which can cause significant sedation like Amitriptyline. Also, alcohol itself can worsen depression or manic symptoms by itself, specially in a patient with a history of depression in past. In some patient it can precipitate psychotic symptoms too.
further, when taken for long term, Alcohol itself can cause insomnia and therefore should not be used as a medicine for sleeping.Alcohol and Depression
Therefore you can see that combination of alcohol and Amitriptyline can have serious adverse effect on your mental health.
It is very much likely that the combination of alcohol with Amitriptyline you are taking currently is behind your feeling irritable and acting out in rage. Please note that this combination has more chances of further destabilizing your mood.
I hope your doctor is aware of this fact that you are taking Amitriptyline with alcohol, if not, you should tell him or her about it.
In current scenario also, Benzodiazepine like Lorazepam or Clonazepam can be very helpful in treating your alcohol abuse
and will also help in sleeping.
In addition to medicines, psychotherapy specially Cognitive Behavior Therapy can be a very good option in your case if you have not tried it yet.
You can try free online CBT via some websites. I am giving below the link to one of them.
Regarding your pets, I don't think that you are being cruel to them specially because you are aware of your feelings and feel bad later on.