Venting session or what?

Wow I just re read what I just wrote and realized that I have a lot of angry in me. I am venting only because I can't figure what to do with the emotions anymore. It would be so much better to have another adult to talk to but because I am alone in this, this is my way to "talk it out".
Don't get me wrong, not every single day is terrible but just about. I think they both have decided to take turns in being difficult. If it's not me arm wrestling with the younger one about her grades and going to school, its the 14 yr old giving me attitude about one thing or another. No wonder I don't sleep most nights! I feel tired, sad, exhausted and lonely. What ever happened to my sweet little angels that used to do almost anything to please me. It was always "yes mommy". Now my home is filled with loud voices of shouting matches....btwn all 3 of us. I want some stability back in the household, sanity. I want some control again...over the girls and over me.

Just last night for example, the 12 yr. old, Sandy absolutely refused to do her homework after dinner as promised. No matter what I threatened her with or how much I told her that she would get grounded, lose her weekends and no TV she refused to get her work done. Nothing would make her budge from the couch. Finally after I had enough, I turned off the TV and made her sit in the dark because she refused to go to her room. It took everything in me to not grab her by the arm and drag her into her room. I don't understand why she really just doesn't care. When she gets in one of those kinds of moods, nothing, I mean nothing will change her mind. Why is she like this?

I feel so stressed. I need to find some escape for me. I can feel my body shutting down-literally.

Single mom new at this

Ok here goes...its been a while since I've thought of trying this but really don't know where to start..and still don't. Somehow it just feels like this may be the right time to just get started. The challenge is finding a topic.
And finding a topic that may be of interest to you?
First thing that comes to mind is parenting only because this is what I mostly do. I am a single mom to two teenage daughters. The youngest is 12 and the oldest is 14. Both are going on their 20's! Yikes! Love them more than anything, but finding it very difficult, no impossible to handle the moods, hormones, emotions and fighting. I need an escape and maybe this is why I am on here. I feel frustrated and a bit guilty because I am at a point that I really don't like being around them. Wow does that make me the worst mom ever?? Does any other mom feel like this or am I just terrible??