Hey @dgperez - that's a tough situation, but likely a fixable one!
I'd start by reviewing your full credit info, are you sure that 1 missed payment was the only thing that changed? Inquiries, new cards, credit utilization (how much you've put on your credit card and haven't paid off yet), and other things impact the credit score.
One thing you might want to try is to call that credit card company and ask if they'll remove that single missed payment from your report. Folks have had success with that in the past, and as long as your account is in good standing, they may be willing to help. A couple minutes on the phone could go a long way 🙂
Hope that helps and let me know how it works out!