One of those days

I seriously just about had a melt down. My son was acting out so I told him to go to his room and go to sleep and he sit there and was screaming at the top of his lungs "I don't want to go to sleep" and all sorts of other stuff(he is four btw) and I kept telling him to be quite and stop yelling and he wouldn't. He just kept doing it. Finally I went in and spanked him twice and he kept doing it no matter how many times I told him to stop. I finally had to call his dad in from outside to come in and talk to him. As soon as his dad came in he was perfectly fine. I was in tears by this poing. I am so damn frustrated. My husband is leaving for basic training in less then 3 months and I can't even control him. What am I supposed to do? I am losing my mind with him. He is always talking back, and whines when I tell him to do anything. I don't know how to handle him acting like this. Even if I do spank him it doesn't do any good. It's not like he is a bad kid or something; he isn't. He is very good he is just always whining when I tell him to do something and always has an attitude and talks back to me. (NEVER to his dad) I don't know if it's me getting more frustrated then usual because of the new baby, or if this is really happening. Am I just being more irritable. I don't know. I feel so guilty sometimes because I know that I give Natalie more attention and I get angry with him when he is jumping around her and stuff, but she is a baby and she needs more attention. I love my son, I do, but I don't know how I am supposed to deal with him when my husband is gone. Frankley this scares the shit out of me. I have been super stressed latley thinking about him leaving. That's one more thing I need to add to the list.