Yeast diaper rash?

My daughter has had a yeast diaper rash since 8/9. I feel like it goes away or gets better then comes back. We’re almost at the two week mark of being on nystatin 2-3x a day but it hasn’t let up. Shes also on cortisone for the itching. She’s soo itchy under her belly button. We’ve been doing breastmilk baths to soak in with a little baking soda or oatmeal, and I let her go diaper free as much as possible. To make matters worse, she broke out in a different rash two days ago all the way up her back to her neck and all up her belly. No rash on her arms or legs. . Took her to the dr yesterday for that and for having a hoarse voice. The dr saw her throat was red, did a strep test which came back negative. Sent her home saying it’s viral. I also haven’t been feeling well and now my dr wants me to go for a covid test. Neither one of us have run any fevers. But I can’t help but be nervous. Anyone have any tips??? I’m so worn down😫😫😫😫