Oh, dear, there's no need to be shy. <3
While I totally understand being shy (when I first joined FH, I was the exact same way), but realize that being with your friend/character's mate, and now inside a pack just gives you the opportunity to make new friends, who very well may be your buddies for a very long time in FH.
So, I don't think shyness is a good reason to leave your pack before you even know them.. You know? -offers you a hug- <3 Just go out there and say hello. c: After all, this is your own "pack" of potential friends, in a way. I know you said you've been there for a week, but I'd suggest trying a little more, and maybe put yourself out of your comfort zone and try to strike up a conversation, or some fun roleplay with your pack members.
But, if it still doesn't work out after a few days of trying this, then simply go and speak with your friend who asked you to join. Let them know that you just don't feel like you're meshing very well with the pack, and that you appreciate them introducing you to this RP, even though you feel it's time to leave.
It'll be okay, floof, and don't be embarrassed to ask for help around here, either. c: Take care, and I hope you work things out with your pack!