I feel so sad to say, "I can't stand my 3yr old son".

I am pregnant with baby #2 and my 3yr old son has been acting up. Today, I took him out to lunch with a friend and he was acting up. My mom and sister came over and his been really active, we also went to go grap some pizza. He was all over the store, touching stuff not to mention on the way to the car he almost made me trip with belly down and all! When we got dropped off, he was playing with rocks and I told them that its dirty there and he tried to run away from me and almost got hit by a car! I felt like I was either going to lose my unborn child or my born child. It been really tough to deal with him in general specially when we go out. Dad is in the picture & lives with us, but he works full time and goes to school full time and most of the time it's just me. I need advise tips anything. He does goes to school full time and he goes to the same school where I work, but I dont swe him all day until I get off work.