Newborn won't leave my breast for 7 hours

I'm in areal dilemma. I have a newborn and today is her second day. She was breastfeeding normally in the hospital and yesterday and from midnight last night she has been completely attached to my breast. That's 7 and a half hours , she just falls asleep on my breast and if I move her she cries and cries and acts as if she's starving . I'm worried im not producing enough food for her as I know in these days I don't have any milk. Please help , my nipples are a complete write off and it's only been a day !