Pooping and cranky baby

My baby is 8 months old and recently she's been pooping alot of times in a day. She's fully on breastmilk (latched and pumped) and 2 solid meals a day. She can play and laugh with me then the next minute, she gets super cranky and cry until very miserable. She used to sleep thru the night when she's about 3 months old but now she starts to wake up in the middle of the night about 2 to 4 times. I have to latch her about 5 to 10 minutes before she goes back to sleep. I don't know what's wrong with her. Any mummies has the same encounter? Mind sharing to me so at least I have some ideas on what's happening with my baby? I feel so drained out everyday now.