Baby hasn't popped

M
Hey all!  My baby is almost 3 months. Well she hasn't pooped in 48 hours. The question is when do I start to worry. She seems to be ok but she gets fussy and does fart from time. To time. She normally poops every day and sometimes more. She is still eating about 5-7 times a day and this morning she at almost 7 ounces. 
Still nothing! Anyone experience this. Oh I only give her breast milk! I pump and bf her through the day and night