Platy pregnant or sick?

So I have 4 platies (1 male 3 females) one of my females has a very large belly. She looks pregnant but it's been like that for over a month. I'm wondering if she's sick? I'm new to this. I will attach a picture if I can. Thank you.

She looks pregnant to me, has she been refusing food, hiding, or acting lethargic?

No she's acting pretty normal. She's huge and it seems she's been huge for a long time! I'll keep an eye on her thanks