Sharing Our Innermost Thoughts

Hey
I was invited to a friend’s birthday party today. I went there just for formality. These days I don’t feel like going out, dressing up and meeting people. I just go for the sake of formality and because I can say a clear “NO” to the invitation.
I went there. Met new people. I feel left out. I had urge to leave and come back asap. I told my friend that i will have to go early, but they keep insisting to say longer. I couldn’t say no, so i stayed. But i feel so bad. I came back with everyone. I am home now. I still feel bad meeting so many people. Now i just want to isolate from everyone for next few days…
Why do i feel so?
I was not like this.
I use to enjoy dressing up & going out with friends. But now i feel like i cannot pretend to be okay or happy in front of everyone. I am tired…
Is this okay.?
Do you feel same?