ggplot如何调整y轴的标志顺序

原代码是：
ggplot(GO,aes(GO_Category,GO_term))+ geom_point(aes(size=Count,color=pvalue,shape=GO_Category, group=GO_Category)) +scale_color_gradient(low="blue",high="red")+labs(color="Pvalue",size="ProteinNumber", shape="GO Category", x="GO Category",y="GO description",title="GO enrichment")+scale_x_discrete(breaks=c("Biological process","Cellular component","Molecular function"),labels= c("Biological\nprocess","Cellular\ncomponent","Molecular\nfunction"))+ theme_bw()
默认的y轴的GO term是按照首字母进行排序的，我需要把y轴的GO term分别按照GO Category集中起来，并最好能按照气泡大小排一下序，请教各位，该如何调整？

您好，请问您解决了吗？我也遇到了一样的问题。没找到代码应该怎么写？