Do I need to blame myself ?!

I have a 3yo and a 8w old. Ever since we brought baby sister home, I have noticed a huge change in our sons behavior.

He love his sister, like too much sometimes. I feel like I’ve done a great job including him, putting sister down when I can, listening when he talks .. it’s just hard .. no one is perfect.

Me and my husband have always been believers of spanking, but since we brought sister home and his behavior has worsened- idk how or what to think anymore.

I almost feel like his mimicking our behavior. He’s starting to yell at us. Like if he doesn’t get his way, he yells- like screams at the top of his lungs.

The last wk, I have tried something new to see if it helps or changes anything. I have tried no spanking and when he responds to something he doesn’t like with yelling, I mostly ignore it.. and/or tell him that’s not how we treat ppl/ react to things.. I do this calmly and just talk to him.

The last 2-3 days I feel like he’s taking advantage of it and walking all over me.

So tonight he got upset I wouldn’t let him sleep with all his stuff animals, I told him to pick 2. He freaked out started yelling, so I warned him and told him if he continued to act like that he wouldn’t sleep w any- so he continued and I took them and put them up. He lost it. Yelled, throwing stuff- so I reacted how I used to and popped his bottom and raised my voice and told him to stop acting like that. And he swung back at me! Never once had he done that ! So I got up and walked out of his room, watching him completely destroy his bed on the Monitor.. he stripped it all while screaming at the top of his lungs. I let him do it, trying to ignore it. After 5 mins, he came out of his room screaming he loved me and missed me. So I went back in they calmly telling him we don’t act like that when we are mad — and laid with him for a second- this time having his sister w me cause I was nursing her. He started to ask for his stuff animals again and i told him they were in time out bc of how he acted he started to flip his shit again. So I got up and walked out..

Like what am I doing wrong?! Do I continue on this ignoring streak I was trying to do.. and cont telling him his behavior is not ok..

Or go back to spanking and letting him know he can’t act like that and if he is disrespectful to me or anyone or anything else there will be a problem ?!

Mommying is so hard 😥😥😥