The fact that the chocobo is lovesick has nothing to do with the fact that you arranged for it to breed. The "lovesick" status ailment is happening all over the place right now, and mostly to people who have never arranged for a Chocodate.
It happened to mine, in fact, and I've never arranged for breeding. Your chocobo and Nomar's may have gotten together, but the "lovesick" status is almost definitely not over Nomar's chocobo.
I'm sure there's something you're meant to do during this time, but breeding is probably not it ... it hasn't helped anyone with the "lovesick" status, and that makes a great deal of sense. Just because you're in love with someone in particular, after all, doesn't mean you're going to feel any better by banging a complete stranger your parents set up for you, right?
No, for the most part, this has just been wearing off on its own. It lasted only one day on mine, and I got the "everything is back to normal" message after that. I took no action that I wouldn't otherwise have done throughout the course of my normal care day.
It's been lasting two or three days for other people, and lots of folks are trying to figure out what to do with it, but so far we've discovered:
1) Cupid worm does nothing.
2) Breeding does nothing, even with a partner the chocobo has already bred with.
3) Exercising in a group does nothing.
All you can do is wait for it to go away, at this point.