Baby won’t sleep without finger

My beautiful baby girl is 4 days old and I already have two problems. breastfeeding makes her fall asleep before she’s done eating, and then she does inefficient sleep-sucking and will wake up if put to bed. I tried giving her my pinky instead of nipple when it drags out too long, but the problem is she’ll wake up if I remove it. She will suck forever. Any pro moms out there with helpful advice?