Lamentations 5:13 (ESV)

13 Young men are compelled to grind at the mill, and boys stagger under loads of wood.

Young Jewish men had to do work that was meant for slaves, or else at least for women (see Judges 16:21; Exodus 11:5): they had to grind grain at the millstones. Small boys had to carry wood much too heavy for them and under which they collapsed. Possibly, this wood would be sold at high prices to the Jews themselves.