I'm an extrovert but I'm not a stereotypical extrovert who hangs out 24/7 and is never home so I can't help with the "staying extroverted" part I'm afraid.
And if you're an introvert like my boyfriend, you have to respect your personality and needs.
The not feeling good enough I can relate to. Many face their own self criticm that beats them down to the ground. I have days where I feel horrible about myself and days where I feel great.
Universally we all matter. But it's up to each and everyone of us to support that stance.
My best advice is hang out and date yourself, get comfortable with who you are. Don't make excuses for what you like or dislike. Respect your person and identity.
That way you will be less hurt if someone dislike you / reject you through out life.
See each chance at meeting people as an open book. A new story unfolds. What happens. You'll see. Embrace it. Live a little.
If it's strong anxiety in the way I reccommend therapy help. Some things are too difficult to deal with on your own.