Breathe! Before you think another thought, simply Breathe. It is going to be OK.
Children sense our stress, and often act out based on it. This may sound counter productive, but the next time he acts out, instead of escalating it; ask him if he needs a hug.
In example: Grocery shopping had become a horrid event for me with my son. He went from being wonderful to acting out, and screaming and kicking me...the firmer and more frustrated I got, the worse he got. Finally, I looked at him one day as he was winding up and I asked him if he needed a hug. He looked completely shocked, nodded his head, and I hugged him. He was already so frustrated with the limitations that were set forth, that he had become insecure and was acting out. While he was still not happy with what he needed to do, knowing that I loved him and understood his frustration seemed to make it easier for him to accept what was expected of him.
Another thing that worked for us was sometimes we each needed some space. When things would get really tense or frustrating, I would ask if he needed quiet time or space. This was a moment when we could both retreat and get ahold of our respective emotions and then resume in a calmer state.
Keep in mind the small things. Try not to get wrapped up and battle the small things. If you have other stressors in your life right now, it gets harder to differentiate between the small things and the important things.
Also, remember, you are mom, and mom is a safe person. Our children will often be their worst to mom. :) I guess it is something written in our genetic code ;)
Finally, treat your child in a way you would like to be treated; with respect, compassion, and understanding. Treat yourself with respect compassion and understanding too.
It will be ok. Just Breathe.