Soooo.
Madoka ran away from home because of ???, found shelter at the bar where she met Ryuu, but sold her body as a side job to pay some woman (potentially her mother?). In the progress she got pregnant at a young age (probably before 16, potentially even as early as 13/14) and following a late abortion became infertile.
And then her lover went and got himself alternative wives.
You can't really blame her for becoming depressed after all (or even part) of this
