My Baby Is 14 Weeks Old Now. From Last 3-4

My baby is 14 weeks old now. From last 3-4 days she refusing to feed.she is a breastfeed baby. After every 7-8 hour she is taking little bit milk. She is passing loose mucus like stools 6-7 times a day. But the amount of loose is only few drops I mean not explosive.It seems that her stomach is hurting her. Sometimes she also showing sign of nausea.she is not sleeping at nighttime.Could you tell me please what can I do in this situation??