Why wont my duck get back in the water?

I hav a 5 yr old rouen female duck and recently she stopped going in the water. she lives on the lake and in her flock are 2 mallard males. recently the 2 males started fighting because it is mating season. one day when i went visit her at the lake i saw her running away while the 2 males were fighting. she went and hid in the brush and when they realized she was gone they went to look for her. they ended up swimming away in the lake. they are gone now but she has continued to camp in the woods for 5 days. ive been feeding her and bringing her a container of fresh water evryday, which she gladly accepts. she has been bathing in a large puddle in the woods. ive looked evrywhere and i cant find a nest. i cant think of any reason for her not to go back into the lake except for maybe shes waiting for her mallard buddies to come back or shes afraid to be on the lake alone. does anyone kno whut she could be up to?