If you don't feel comfortable with the high limit, call them and tell them to lower it.
I used to love having cards with $10,000+ limits, lol, but in reality, having several of those high limit cards go against your credit rating. (Creditors see it as too much credit that you could possibly do harm with.) I pay off my card each month, so I choose to have a limit that I'm comfortable with, just in case, lol.