Seriously?!?!

So, life with two kids is definitely harder than I thought it would be. Not because I have two children that need me constantly, but because I have one that needs me constantly and one that has decided that since I have lots going on it's suddenly OK for him to break every rule he can think of. This fine morning, for example, I was still in bed with the baby feeding him when my oldest started the every-two-minute campaign for breakfast. I calmly informed him that he'd just have to wait and said "why don't you go play, I'll be out as soon as I can." Naturally, I became more terse and annoyed when he came back over and over again to find out if I was going to fix his breakfast now. Then he came back and I got a good look at him. He had apparently colored all over himself with a purple marker. He knows he's not supposed to do that. I told him to go get the marker, throw it in the garbage and go to his room. He blithely replied that it wasn't his marker, but one of daddy's pens, which he knows he's not supposed to play with. I wasn't sure I believed him since he's shown a great capacity for lying through his randomly-placed teeth these days. I told him to go get the pen and bring it in so I could see it. He left for about five minutes and then came back to inform me that he couldn't find the pen. I responded that he'd better find it or there was going to be trouble. BIG trouble. He immediately started whining that he COULDN'T find it anywhere and that it was lost and when was I going to make breakfast? I became irate. I quickly changed the baby's diaper and headed into the living room. After loading the baby into his swing for his morning nap I looked around at all the places likely to be harboring a pen that Corb had used. It wasn't in any of the usual places. I called my hubby and asked him if he had left a purple pen in the living room and he said he had but that it was a fine-point pen and not a marker. I was more convinced that Corb was lying since the marks all over him were fat, like those from a marker or felt tip, not a fine-point pen. Of course I couldn't find a purple marker either. After practically turning the recliner upside-down I found the cap to a purple Uniball pen. Ok, so it was daddy's pen. At this point, rules broken included coloring on himself, using daddy's pen, losing daddy's pen, and losing it without the lid since it is now probably staining the hell out of whatever it's on. I told him he'd better get started washing all the ink off. It only took sending him back to the bathroom five or six times to get him reasonably clean. I cringe to think what the washcloth and towel look like, I should check that. When I was telling him that he was in big trouble for breaking all these rules and that he needed to spend time in his room this morning he got angry and ran to his room, slamming the door as hard as he could. I couldn't do anything about it that second, as I was feeding the baby again, but he must have figured out that I was going to be seriously pissed as he appeared in front of me about two minutes later and gave me a breezy, offhand apology for being a "brat." I said he should be since he would now be forgoing the trip to the Pumpkin Patch planned for this weekend. I made him some waffles and made him eat them in the doorway to his room and then into his room he went. I figured that he would behave for the rest of the day, but that was apparently too much to hope for as I just had to go in again to take his cars away. I heard one hit the wall and went in to hear his explanation as to why that might be. First he lied and said it tipped over, but then I found the car under the crib about three feet away from him. He then said that he was playing with the car and it just flew over there. After telling him that cars don't "just fly anywhere" he admitted that he threw it. He lost his cars for throwing toys (against the rules and he knows it) and lying (ditto). That didn't stop him from threatening me while I was taking his toys away, though. At this point, I'm not even sure where we progress from here. He doesn't have much of anything left for me to take away. I made sure to tell him that he'd better pull himself together if he wants to participate in Halloween this year and that if he didn't I'd be taking his Halloween costume back to the store. He informed me that he will run away and kill himself (where the hell did that come from??) and that he doesn't care what I do. I'm getting to the point of being so tired of his behavior, which has been relentless for weeks, that I don't really want to be around him even when he is behaving. I'm tired of being lied to, disobeyed and disrespected. Especially since I work so hard to make sure that his life and all the things in it stay on track. I work on his homework with him, take him to the library, drive him all over hell and gone every day, tickle and wrestle with him in the evening when his dad gets home, and on and on it goes. I know moms are generally unappreciated but I think this is more. What could have possibly made him decide that the rules don't apply to him all of a sudden? Where did this blithe attitude come from? Where on earth did he even hear the "running away" and "going to kill myself" strategies? I'm at a loss.