Finally the TRUTH comes out!

I've been wanting to blog for years now. Not that I think anyone will read it, I just need to get all this shit out of my head. At this moment it's mother's day weekend my husband is mad at me, my 7 year just claimed she didn't love me anymore and the 4 year old is continuing his barrage of automatic weapon sounds that he has going since 6am. It's one of those days like most where i just feel like I can't do many things right as a mother. I"m trying to pull from all of my parenting classes each time a situation comes up (about every 2 minutes) with one of my kids. My brain is fairly slow after having two kids and I never come up with the right solution. So I"m left with my feelings and thoughts about how I handled that, "oh i should have done this or that" or "oh man i sound just like my parents and that is so wrong!"
The most recent run in with my kids and why my daughter now doesn't love me is this:

I asked the daughter 5 times to pick up her room, she kept refusing, then started lying that she did it, then used the old "no one ever helps me or loves me" routine. Keep in mind that the things on her floor are pieces to puzzles, pencils, doll head etc....things not too hard to put away. I didn't loose my cool told her "let's go see if it's all picked up now since you said it was." Standing at the door i see all the above stuff still all over floor. "I thought you said you picked it up" I asked her. "I did pick it up, I told you that" she yells. I am now starting the wheels spinning, OK-what do i do, she's already her room so a time out is useless, I've already asked several times for her to pick up.......yelling doesn't work so what to do?? "What about your shoes?" I ask as I look around at the 3 pairs strewn across the floor. "I picked up my shoes already" says the clearly demon possessed 7 year old. Now I'm going back to what a preschool director once told me, remember whatever you threaten you have to follow through with or your word means nothing. "Listen I see your frustrated but I need you to pick up your stuff and if you don't I will throw it away" I say very calmly. Is this the right approach? I have no friggen idea but I'm trying to keep my cool here and stop the 7 year old from running the show. "Fine throw it all away!" screams the 7 year old. I go to get a trash bag, start throwing books (that i later give to son), pencils, pieces of paper, headbands..all away. Now the screaming really begins "I don't love you anymore, you're not my friend! I want my stuff back now!" Amazingly this whole time I didn't' yell although I want to and i just threw the stuff out.
I'm guessing we just had another example of "how not to be a good parent" otherwise known as "welcome to imperfect parent world!"
Seriously......how the frack (to quote BSG) should I know how to handle possessed children?