mommy guilt

Do you ever feel like your a bad parent? I'm sure you do I'm sure we all do. Its not a good feeling. I'm always doubting myself, and even losing my temper. It seems like I've been losing it a lot lately. I've been told that "If you are a bad parent you would not be worried about being a bad parent," So I guess that's a good thing. I just HATE feeling that I've done something wrong or scarred them for life. As the kids get older it seems they are more determined to drive me completely nuts, from Morgan arguing about homework, to throwing a fit when I ask her to turn off her light if she's not in her room. Then from Logan acting totally out of control and embarrassing me by running around out of control in the grocery store to, cutting the sides of his hair right AFTER I took him for a hair cut. I know I know this is all normal, then why do I feel so out of control? At the end of the day I find myself apologizing for yelling or my short fuse, then praising them telling them "thank you for being such a good boy today I'm so proud of you." Usually both kids look at me like I'm insane and say "um we got busted today, or mommy you yelled at us today," and here I go again saying I know but that was just a small part of the day, when really it was HUGE chunk of the day. I go to bed feeling crappy and just wanting to go into their room and hug them telling them how much I love them. I'm sure I'm making it sound like I'm Mommy dearest, I know its not that bad. I just guess everyone has room for improvement. And I'm vowing to have more patience, and try to enjoy my kids a bit more everyday..