Sometimes you’ll be at a large social gathering and you’ll be too quiet (for your liking). You might be intimidated by more vocal members of the group, or just too unsure of yourself to get involved. You’ll berate yourself later for your regression to shyness. It leaves a little dent in your confidence.

Conversely, sometimes you’ll be at a large social gathering and you’ll find your place. You may even be center of attention. People will listen to your opinions and laugh at your jokes. You’re king of the (conversational) world! You’ll congratulate yourself for no longer being shy. Your confidence will pop on a pair of dark shades, stick it’s feet up on the table and lean back in it’s chair in smug self satisfaction.

The thing is, neither of these people is you.

Your level of interaction with people in social situations will always have it’s peaks and troughs. That doesn’t mean you’ve returned to your old bad habits. Sometimes you’ll be tired or uninspired, sometimes you might be unwell - this will have an effect on your ability to talk. Opposite to that, sometimes you’ll be full of energy and ideas, talking to and buzzing from the people in your company.
Either way, keep in mind, as long as you’re still pushing yourself to get out there, turn up to events and meet people, then you’re making progress. And I know how hard that is to do, believe me. You should always pat yourself on the back for making that effort.

(update)