I'd go ahead and start looking for a new job.

double down, already there, go down swinging

> my boss was furious, and I’m not sure what will happen next

I have a pretty good idea

Sometimes errors lead to good outcomes.

Good luck at your new job!

Especially if they already hate it

If you hated it this much, then drunk you did yourself a favor. Instead of staying somewhere you're unhappy get out there and start looking for a better position. Not like you left yourself any other options.

Own it. Write out a better list and list your ideas for solutions. Go directly over your bosses head and give it to their boss.

Tell them you can create a much better work environment if you were in your bosses position. Worst case, when he shows up to say you need to be terminated, it'll look like he's on the defensive now. Maybe you still get fired, but you probably will anyway without doing this. Now if they give your next job a bad review of you, you can say that they were upset you took initiative on solving office problems, then turn it around to how it was a learning experience about doing things the right way. No matter what it sounds better than getting fired cause you did something dumb while drinking.

Best case they fire or move your boss and you get the job.

Just be honest and professional. Looks like you already talked. Maintain that you were venting and the things you said may not represent represent how you truly feel. An honest apology will go a long way.

No place worth working for will fire you over one indiscretion. You will need to repair the relationship over time though.

On the other hand if you truly mean all those things you said and hate working there, it’s a good opportunity to start looking for a better place. No one want to be in a toxic work place, and no one wants to deal with an employee who clearly does not want to be there.

Instead of apologizing, you should have followed up with, "No rush, but I'd mainly like to see improvements in areas A, C, and D. Let me know how you plan to proceed."