breastfeeding newborn

My LO is 3 days old. It is nearly impossible to get her to wake up enough to nurse her. I am supposed to be waking her every 2-3 hours to feed her for 20 minutes at each boob.  I have tried undressing her, skin to skin, cold wipe to the forehead or butt and those things will wake her enough to latch on but then within 2-3 minutes at the breast she is falling back asleep. She is having plenty of wet/dirty diapers so I am pretty sure she is getting enough to eat, I am just really concerned about establishing a good milk supply over these next couple weeks. I am a FTM and sleep deprived and just want to cry. Any help or ideas is much appreciated it. Thank you!