Well then stop being friends with Carl cause Carl is fake for doing that. Get your boyfriend back, but if he doesn't want to then forget about him too. I understand that you miss your boyfriend cause I was in this situation too, but I finally moved on.
You just broke up today, why break up if you want to get back with him? And if it is him that ended it, then asking him put the same day he broke it off isn't a good look and you will regret it later. Best thing to do, keep busy even when all you want to do is mope at home, get out and about, always look your best, make sure he knows what he is missing. Don't call him or txt him, make him start to worry that maybe he made a big mistake.
Of course if you dumped him and now regret it, then you need to consider why you dumped him in the first place? Has that changed if not have you now decided you are happy tout up with whatever it was that caused you to dump him? If you broke it off and realize you were totally wrong to do so and want to stay with him exactly as he is (not fix him) then time to call him, apologize and explain why you did it and how you know you wont do it again.