Help please, feeling so lost.

I’m a first time mom and have a 3 week old. I find myself struggling a bit right now. I find my baby breast feeds for about 30-45 min. I know babies should only stay awake at this age for about 45-60 min. She fights falling asleep after eating. This is where I’m struggling, sometimes she’ll fall asleep after the feeds but as soon as I lay her down she’s wide awake. (She seems like a very alert and stimulated baby) I do have the room dark and white noise on. She will lay there but then starts to fuss. Because she is so little still do I pick her up and try to rock to sleep or give a pacifier or do I let her lay there and not pick her up till she’s really crying. I struggle with this because I hear how new babies need that nurturing and don’t have the brain power to fall asleep drowsy but awake yet. I also know if she’s been up for 1.5 to 2 hours she’s probably over tired and needs to get to sleep but sometimes too I just don’t have it in me to rock her for ever, but feel guilty letting her lay awake in the crib fussing a bit when I know she needs sleep? I have used the swing but I also don’t want her to rely on the swing and pacifier to always fall asleep? I find I feel this way because one book I read says let your baby fall asleep on its own and another says baby needs you right now? I feel like an emotional wreck because I don’t know which thing to listen to. On one hand I feel guilty and like a bad mom in the other I’m like I don’t want her to pick bad habits up but I know sleep is very important for a new baby.