My kids make me SCREAM!

I know I'm the adult, and I should be more in control, but DUDE!!! They don't freakin listen! Like ever, unless I get MAD! My step son is almost 10. He still pees the bed and wears a pull up to bed. He thinks it's perfectly fine to wander around the house with the pull up on till afternoon....he even said it's cause he's LAZY! The other day he pooped his pants TWICE at his friends house AND tried to deny it. OMG! We have discussed the possibility of anything from abuse to a medical issue and he swears he's just lazy. Today I came home and he is laying in pj's playing xbox. Wearing a pull-up. The laundry he was supposed to do yesterday still dumped all over. Living room scattered with 7 nerf guns that are supposed to stay in his room. I'm TIRED today, I flipped out. I didn't call him bad words or anything, but I sure wasn't nice about it. I totally screamed at him, and went to my room. That's not who I want to be. I'm just so frustrated! Any advice from other frustrated step mom's or moms?