My boys are just out of control :-(

I have always tried to be a gentle parent with them but also give them clear boundaries. I let them explore and be kids as much as possible.

They just walk all over me...how can a 2 and a4 year old be ruling our lives like they are?
I totally lost it the other morning...I asked and asked for them to pack up the toys in their room and get dressed and stop fighting when ds2 kicked ds1 in the head. I had had enough so they both got smacks :-( I never hit them I was just so frustrated that they don't listen....have I done the wrong thing in how I raise them!
Dh has no patience so I try to be the calm one who tries to parent them as little smart people not as dumb kids. It's so disheartening..I thought I was doing the right thing with natural gentle parenting...then I see parents who are the opposite and the kids are so well behaved :-(
I just want them to be respectful and to be kinder.
I just feel like I am failing them :-(