I am not derailing anything. I’ll give it to you straight up.
The Bible makes it clear in many places that drunkenness is a sin. Note: I did not say “The Bible makes it clear…that drinking alcohol is a sin.” I didn’t say that. That’s not what the Bible says. But the Bible DOES say that drunkenness is sin.
In the United States, drunkenness is a measurable condition by lab testing. A certain level of alcohol in the blood means that the “tipsy” person in question is considered legally “drunk.”
Every person will vary as to how much alcohol they must consume before their blood alcohol level is high enough to call them legally drunk.
But tipsiness is generally a sign that if the person had their blood alcohol level measured, it would very likely be high enough to be considered legally drunk in the U.S.
If the tipsy person is “drunk”, it does not matter if they are causing harm or not. Drunkenness in and of itself, with no harm done to anyone, is called “sin” in the Bible.
Since the OP did not have their blood alcohol measured, there is no way for them to know whether they were legally drunk. But if they know, based on their degree of tipsiness, that they were not fit to drive a vehicle, then there is a good chance that they were drunk, and that is sin.
I can’t say whether it was mortal sin or not. It would seem not, since the OP was not deliberately attempting to become drunk, and it seems that the OP, along with many other Catholics, is not convinced that drunkenness is a even sin.