Before you set off a panic, I assume you're talking about the Peds specialty matches, not the main Peds match. Of which there's only one.
You should call the NRMP. Not submitting a list is perfectly fine. You should be able to register for the new match, and the two timelines don't seem to overlap. In any case, the NRMP should be able to sort it out for you.
Alternatively, if you log into your R3 account you should be able to see which matches you're registered for. If you're still listed in the Spring Peds Fellowship match (even though it's over), you might need to officially "withdraw" from it before proceeding.
Still, even if you check and that seems to be the case, I wouldn't proceed until you talk to NRMP tomorrow.