Unruly son

Okay mommas I need some advice.

My 6.5 yr old son lately has been really disrespectful towards me.

When he doesn't get his way or is told to do something he doesn't want to do he completely shuts down , or ignores me. Sometimes he straight up tells me no...

I just don't understand, I'm a very loving mom and I think he is taking advantage of that.

On the other hand I am by far a push over, I have rules and consequences for bad behavior and additudes.

I've tried everything it seems... I try to talk it out with him, try to get him to open up to see if something more is going on inside him, I've tried time outs, grounding to his room til dinnertime or bed time, I've taken away his most prized possessions.

It's really stressing me out as I have a new baby due any day now. I'm dreading having to deal with his additude problem on top of being sleep deprived.

Many ppl have said it could be the big change of havi ng a new baby (he has a sister 1.5 yr younger than him) although he is very excited for the baby to come and constantly hugs, kisses and talks to the baby. I've made sure to make both my kids feel just as important as the baby that is about to arrive so I'm not sure it's the issue.

Any advice on what worked for you would help a lot, also is this also normal for his age?

Thank you so much, sorry not too sure where to post this