Any suggestions?

I love my son. He is the sweetest kid. He goes around the house telling me he love me and that I'm beautiful. But at church this last Sunday it was almost the end of his short lived life. J wasn't able to be there as it was his guard weekend so it was just me and A. He was really good, up until about the last 10 minutes of sacrament meeting. He was mad at me that I hadn't brought fruit snacks for him so he was sulking on the floor. As we were getting ready to sing the closing song, he started to scoot underneath my chair. I told him to stop and sit up so we can get ready for prayer. His reply "I don't want you mom." So my thought "Oh great. Maybe if I just ignore the behavior it will stop." So once sacrament meeting was over I got up and headed to the Sunbeam classroom to drop off my stuff for the lesson. All the way down the hall my son keeps repeating " I don't want you mom!" Other parents look at me and comment "Yeah my kid has done that to me." With that info I was feeling a little better, but still very unhappy with his actions. Since our Primary has opening exercises in the Chapel I was heading back there when I felt A smack my back while still screaming at me. I told him to not hit but kept walking to the chapel. As I entered my partner asked if she needed to take him for me. I declined and explained my strategy of ignoring the behaviour and sat down on our assigned bench. I noticed that A was no longer screaming at me anymore, but I couldn't see him from where I was. One of the other Primary teachers came up and said "A is sitting in the doorway between the chapel and the hallway." I debated going back there but figured he would get bored of that and come to sunbeams. Nope. I was wrong. So the primary president, who also happens to be my friend and neighbor, decided to step in and help. Well, unluckily for her, A snapped and started hitting, spitting and screaming at her. I just started crying. I was so embarrassed and humiliated. My sweet little son had turned into a possessed spitting-kicking-screaming monster. The primary president was able to get A to finally sit on our bench and sit still. I tried my best to clean up my make-up which is kind of hard to do without a mirror.After they excused us to go to sharing time A ran after me crying. So I just scooped him up and carried him. Once in sharing time I explained to him as calmly as I could that he needed to tell the primary president he was sorry otherwise he couldn't stay on my lap. So he went to her and told her he was sorry. I was thankful for that. Once in class though he started acting up again. This is not the only time he's acted up. In fact it was so bad one week that A made J go to class with him in the hopes that would cure his actions. A was more then happy to be back in sunbeams the next week, but apparently that lesson was already forgotten. So what do I do? Do I tell the primary president I can't be a teacher anymore? How do I correct A's behavior?