Just keep nursing. The more she suckles, the more milk you will make. Just keep her to the breast. Newborn babies have tiny, tiny stomachs. Like the size of a walnut tiny. So even if you think you're not making enough, judge by her diapers, not how much you think she's getting. As long as she has several wet diapers per day, and she makes a poop every few days, you're doing just fine.
Just keep at it! A lot of women think they dont have enough milk at first, but your baby is part of you, she will tell you what she needs, and they naturally seem to adjust your body to their needs. Just be patient, and make sure you take care of yourself too. I unfortunately lost mt ability to make milk after a move, the holidays, and just being so overwhelmingly busy I stopped producing after 8 months. My second one has been SOOOO much easier with that in mind. So take care of yourself, relax, get your fluids and enjoy your private time with her!! She will let you know when she needs you, and your body will too.