7m old has a cold

she’s congested more at night with slight coughing through the day. She’s breast feeding so it’s hard for her to eat this time around. I’m a first time mom with virtually no help. Is there any recommendations of what I should buy or should be doing? I seriously am so lost. Dr recommended she get lots of milk but it’s hard to get her to eat. She’s playing and acting like her normal cheerful self.