Loving someone who has a serious mental health condition can be a challenging and confusing relationship to navigate. It's important to know a few things in order to support and love them through it.
Their mood is not because of you. Just because you may feel like have to be careful of what you say, just because you don't say the perfect thing, doesn't mean their whole mood is because of you.
Somedays are better than others. Each day can feel different and it's important to know that the good days may not always last all week, but either will the hard days.
It's okay to ask them how they are feeling specifically. If you have a close relationship with them, it's important to ask the loving but hard questions sometimes.
Use the language they are using to describe their illness or state of being. Don't use words they aren't comfortable using to describe what is going on in their life.
They can't just "snap out of it" so don't expect them too.
They care about you also, it's just hard to show it right now.
Check back to read about boundaries that can be important to put in place when loving someone with a mental health condition.