I deleted my 360 page, but now I can no longer login into my regular email, why is that?

Well, since the only way to delete your 360 page is to delete your entire email account, the two being interconnected, my guess would be that you misunderstood that what you were doing would deactivate your entire Yahoo! account. That's why it is so important to read the instructions carefully when you click on a link that tells you how to delete something because with Yahoo! you almost always have to delete your entire account in order to get out of such services as Answers and 360. But if it's of any consolation to you, the name should become available again in a little over 90 days, thus, you can reclaim it as a new email account or a public profile thereof.