Very happy/healthy cat has dilated eyes acting aggressive?

[jkb0159]

Our very affectionate and loving cat has been “acting out” the past few days- I noticed she seems to possibly have a hair ball she might be trying to cough up the past few days but only coughs a tiny bit and then stops- but in that same time period she’s been very irritated and her eyes are dilated fully when she’s normally calm. Her easy are tell- always have been! We can tell exactly what her mood is by her eye dilation lol. She’s just been acting strange the past few days- I’m wondering if she might have a hair ball that she doesn’t know what it is and that is why she 1.) isn’t coughing it up (she’s never had one before) or 2.) it could be something else and she isn’t feeling good so is being irritable.
P.s. Her eyes have been fully dilated every time she’s been “aggressive”. That’s not normal. Usually she calms down really quick and her eyes match her mood.