Hi, Kataangfanficer,
Sorry this is frustrating you. Let's see if we can help.
First off, what OS and browsers are you using?
There should be no fundamental difference in logging in on the new domain. You use the login boxes in the upper right corner, and passwords are case sensitive, like before. If you can be more specific about where the errors occur, and exactly what happens, we can be a little better at pinpointing the issue and helping to resolve it.
Thanks!