Ok how do you know if your baby has thrush? The little boy I've been having to take care of has it…

Ok how do you know if your baby has thrush? The little boy I've been having to take care of has it and I'm now worried that my daughter has it. She doesn't have any problems latching or eating normal foods. She does have white stuff on the sides of her mouth though and I'm so worried now. Plus I have a weird red spot next to my nipple on the right boob... I'm so worried now it's not even funny. 😭😢😭😢😭😢😭😢😭😢