That used to be me too, but there is a better way of dealing with this and it starts with you. I am not a trained professional but from what you shared, it sounds like you are totally stressed out and possibly have some anger or frustration issues. You need to get in touch with your feelings. You have to figure out what your issues are and then take responsibility for your actions instead of 'checking out'. You are most likely 'checking out' cause you can't cope with the situation at hand. If you are indeed stressed out, figure out what is stressing you and take action. If the kids are screaming, fighting, or just running around, you unfortunately don't have control. Thus you have to take control by scheduling their time, and/or scheduling an activity with them. By all means SHUT OFF THE TV! You may need to ask for help from your spouse, relative or a friend so you can get on top of things. If they are old enough, give the kids a list of things to do or that can be done, remember kids love structure. Another thing, work with your spouse, relative, or friend to try to schedule some time for yourself.
If you have anger issues please identify where those are coming from so you can make a conscious effort not to take it out on your kids. I feel that when we yell at our kids we are essentially asking them to pay for our feelings. Kind of a 'I feel bad so I am going to make you feel bad' thing.
I too have done all the things you have said you do, and have felt like a bad parent. We aren't necessarily bad parents, we have just picked a bad parenting style. Further more, the guilt you feel, for pushing them away and yelling, just compounds and makes you feel even more angry at yourself, so then it becomes a cycle. Our first clue that we haven't been dealing with the situation the right manner is when it creates bad/guilty feelings for us. When we feel them, that is our cue to step back, take a moment to destress and tackle the situation in a different manner. I have to remind myself, I am the adult and should act like it, and not regress into immature, thus ineffective behavior (and that is what pushing away and yelling is). Choosing the 'easy way out ' in the heat of the moment may seem good at the time, but as we have found, it creates more problems for us than if we were to put in the effort to resolve the true issues, and relate in a more respectful manner everytime. As a result of my change and efforts our house has been less stressful for all.