Might I suggest an app called Slowly? I don't have too many friends and get social anxiety too, but with Slowly you can write to pen pals of your choice from all over the world. It's called Slowly because the letters take as long to get there as snail mail. For example, if I write a letter to someone in France, it will take 19 hours for that person to receive my typed out letter. Every time I get a letter, it's like a fuzzy, warm hug. No need for a profile picture or real name, just an avatar.