be up against (someone or something)

To have to deal or contend with someone or something, especially that which poses a serious challenge or problem. Each year, more and more families are up against debt going into the holiday season. We're up against the only undefeated team in the league next. It's going to be our biggest challenge of the season. Sorry I haven't been in touch recently, I've just really been up against it in work the last few weeks.

be up against it

To have or be likely to face serious problems, stresses, or difficulties. Each year, more and more families are up against it going into the holiday season. Sorry I haven't been in touch recently, I've just really been up against it in work the last few weeks. Now that you're involved with the mayor's office, you'll be up against the very real corruption influencing our local government.