Yurt, I'm so sorry about all you are going through. It's all just lousy stuff, especially losing your cat on top of everything else.
I agree about talking honestly with your daughter. It sounds like you already do that - good for you! It might be good to find an Alateen group for her, too. More than anything it's important not to continue this pattern in her adult life. Most people internalize the patterns of their families of origin so deeply that they have no idea they even do it. I'm 44 and I'm just catching on to how entrenched I am in these habits. Kind of sad.
Just my own opinion here - be careful with your friend. It can be a slippery slope in this kind of situation. You aren't getting much comfort, validation, or companionship at home. It's easy to lose focus on taking care of yourself and fixing yourself when there is something that feels so nice to think about! I lost a lot of time daydreaming about one of my friends that way. Nothing ever 'happened' but I could have been actually dealing with my real life instead of living in a fantasy world all that time. Just some food for thought.
Take care. I'm glad you found SR. It's a godsend.