You know it's been a long day when baby is swaddled and your calling it a night knowing you'll be up…

You know it's been a long day when baby is swaddled and your calling it a night knowing you'll be up at 10:30 or so to feed her again anyways! She barely slept at all today and is only 5 weeks old. Plus she ate 3oz of formula at 5:00 and wanted more at 7:00. Should I try giving her 4 next time or 3 and 1/2? This is all so frustrating sometimes wondering what to do.