First yes you have a CCJ, issued by the courts, if you fall behind on payments the debt becomes payable in full and they can issue a warrant, this does not always have to be with the
county court bailiffs, this could be a writ of Fifi and the first official document with a court stamp you will see is the one the bailiff is carrying on your doorstep.
The easiest thing to do is make the payment that is missed, once this is paid if any warrant is issued it is a simple case of having it suspended at your local court.
When making a missed payment for a CCJ it is very important that it is recorded as the missed payment. And the accompanying letter must be carefully worded, I can help with this letter but would need to know how and when you make the normal monthly payment.