Hi Nofun,
One word in your post sounded alarm bells in my head...Ativan.
Maybe I am not one to give advice as I am not 100% sober yet, but I was put on this drug a few years ago and let me tell you, it is addictive and greatly enhances the effects of alcohol. You should NEVER mix it with the drink. Maybe that is why you are suffering such horrible hangovers after what is not a HUGE amount of alcohol. One thing is for sure, pills and booze are a terrible mix.