Sleepy baby

Hi mummies, ftm here. My baby just turned 1 month and we notice that she has been sleeping more and hence eating less. We have tried to increase the amount per feed but she doesn't finish. Previously she was drinking 90ml every 2 hrs (810ml per day) and now has dropped to 90ml every 3hrs (630ml). Wondering if shld I wake her up to feed her? Or if any other mummies experience this as well?