Used my wildcard already. Tad gutted but my revamped team is gonna GOAT the rest of the season.
I have a habit of using my wildcard early as well, though I try and fend it off for as long as possible. It's a great thing to have going into the last couple of weekends.
I'm pretty sure last season we got two wildcards to play in each half of the season. I think if you use your first one before the January transfer window then you get another one, though I don't think you can stockpile them.