I can not get into my email nor xfinity in general

My brother just got off his email from the same computer  but with a different email address and password and once he logged off I could not get into my emails once I logged into mine.   What is going with Comcast?  I had issues the other night without warning or explantion,  Both my TV and phone which are part of my triple play crashed for over an hour and then my computer was acting the slowest I ever experienced