"She is having a bad day."
Translation:Hon har en dålig dag.
No. We have two ways of expressing a continuous meaning, but neither of them would fit here.
There's a long discussion about the lack of continuous in Swedish here: https://www.duolingo.com/comment/5954508
and our continuous expressions are taught in the skill Continuous here https://www.duolingo.com/skill/sv/Continuous-Forms (this link will only work for users who have reached that skill).
I think it's a good question, actually I think there's a whole subject for a thesis to be found in this, but don't get me started. Anyway I try to answer even old questions in the forums – I realize the person who asked them has probably learned lots 3 months later so they may already know the answer, but if a question has occurred to one person, it's likely to occur to others too.