Single parents need extra support than two parent couples. So find a support group of single parents of teens, and start going there religiously. It will give you the feeling that you have more of a life than you actually have parenting teens!

Second, the boundary issue is they key. Kids don't feel safe without a strong boundary. And when I say strong, I mean you have to hold the line like you were a linebacker for the Pittsburgh defense with some kids. With other kids, the conflict and boundary battering doesn't need to be so intense. But in my experience, it is most often the most intense between same genders, ie mom and daughter, and dad and son. So keep that in mind too.

Third, teens very much need to feel part of a family, yet they are pushing away from the family at the same time. I think it's a good idea to have regular family time with teens, but don't call it that. Don't make it church or school related either. Just make it time to hang together and watch videos, or go shopping, or something everyone likes to do, and then do it regularly. That way you won't feel guilty taking some time for yourself now and then, and they won't feel like "family" is a thing of the past--for little kids.

Lastly, you mentioned something about wanting your daughter to come talk to you when she needs help. This is the biggest mistake parents, but especially single parents make. You need to understand that the reason why strong boundaries are so important is that you want them to be afraid of what you will say, think, or do if you find out about something they know they shouldn't be doing. This is actually their conscience working, as if you were their little angel on the shoulder while they are away from you. They really need you to stay in that role while they are teens. They are going to talk to their friends, not you, almost always at this age. You really need to accept that, and know that if your relationship is strong, they'll come back to you later in life as "friends".

But the teen years aren't the time for being friends with your kids. It is the time for holding the line, so they know how much you care about them, and about the family. Use guilt if it works. By that I mean, you want to appeal to their best sense of judgment. If they do some stupid thing out in the community or at school or through church, let them know how it reflects on you as a parent, and on your family. You wouldn't believe how powerful a motivator that is for kids.

I have a 20 year old and a 17 year old, and work in an urban high school. Believe me, you are not alone in the way you feel. But if you feel like things are getting out of control, it is because they are, and because your child feels out of control. But that is pretty normal, in one sense. But as others have said, if you suspect drug and alcohol issues, sexual promiscuity (for male or female child), gang stuff, anything like that, get to your school's social worker ASAP, and start working with them.

And BTW, declare a new law--forbid smoking. You need to do this as a parent because the effects of smoking on your child's health is really, truly negative. You are being ridiculously permissive about that. "Because they'll do it anyway" is a sign that you aren't parenting. Get some parent training for adolescents, as someone else suggested. A parent should never give any sort of permission for their child to engage in unhealthy or high risk behaviors, just because they don't feel like setting the boundaries.

Parenting teens is hard, thankless work at the time. The reward is the adult they become. No, you won't have much of a life while parenting teens. It's exhausting in the same way parenting toddlers and preschoolers is exhausting, and now you are older and have less energy than you did when they were young. But you are the parent. Not their friend. They have friends. It is really true. Teens aren't friends with their parents during their teens years, unless their parents stick to the script of being the parent first.

People have made good suggestions on getting kids to do what they are told. But the number one way to get compliance with kids this age is to withhold privleges. Phone access, internet access, time out with friends and boyfriends. I spent a good part of my teen years grounded. I'd get out of the house, misbehave again, get grounded again. I'm a slow learner! But the important thing is, my parents not only kept grounding me, but eventually sent me to boarding school to keep me from killing myself with my dangerous, high risk behaviors, like partying, the drink, etc.