Welcome...I'm so sorry things are so stressful. I think Troubledone's post and suggestions make a lot of sense. I don't have any direct experience like this although I do remember how tense and frantic I felt when I allowed myself to be caught in the middle particularly when my daughter was in active addiction and just going through the motions of thinking about sobriety in order to stay in the house. Addiction truly is a family disease.
Is your daughter working a program and does she have a counselor or sponsor she can discuss this with? I understand why you are stressed but maybe this is not your problem to own. Maybe the only part that is yours is to let them both understand how this friction makes you feel?
Lots of hugs. Stick around...there are lots of wonderful folks here and great support!