Please try to get some more sleep, I swear it makes a lot of difference. When we're exhausted our brains are well and truly goosed and focusing your brain is impossible.
As for the social event, would it be a solution to just go for an hour or two to show your face? Then just tell whomever you're going with that you're tired and are going to call it quits early. Least that way they know you made the effort to come but you don't have to be stuck there.
In regards to the mood swings, try to relax more of an evening. Throw a film or tv show, relax with a drink and some food. I find that helps a lot, having my own space before bed time. Feeling at ease on your own time helps settle your emotions day to day.
Stay strong and keep us updated.