Can I import messages into yahoo mail from Thunderbird?

I upgraded to Yahoo Mail Plus for the POP access. Unfortunately, I forgot to turn off "Delete messages from server" in the Thunderbird acccount server options. So when I downloaded my mail, it removed it from the server and now all of those message a no longer accessible with the Yahoo web interface. I'll be pretty screwed if I can't get those back. Is there any way to export from Thunderbird back into Yahoo web mail?