Hello. I understand how it feels to worry about this. I'm sorry. It is true that often, breast cancer doesn't have pain associated with it which is why some women have no idea until they get a mammogram. Itching of breast is also not usually due to cancer. Paget's disease is different but you don't describe this itching being with your nipple. https://www.healthline.com/health/itchy-breast-or-nipple#in-pregnancy
Here are the symptoms of paget's disease: a nipple that appears inverted or flat, inflammation, tingling, or burning; a lump in your breast; bloody or yellow nipple discharge; thickening, flaking, or scaly skin around your nipple.
Could you be pregnant? I'm sure they ruled that out. But hormones can cause this and I know you were tracking your period to see and it is still ongoing but your hormones are still circulating, so that is still a possibility.
Although you don't have any lumps and aren't nursing, mastitis or infection could still be possible too.
I know it is hard NOT to worry. But know you are under care and will be seen soon. And they can determine what is doing on and it is probably nothing. And on the off chance it is cancer causing your symptoms, breast cancer is treatable. It's a highly studied, wide spread cancer that they know so much about that early detection is something you knew to do and you're doing the best you can. Keep yourself busy and distracted until your appointment and let me know how it goes.