Oh my, I was in your shoes a few weeks ago. My son (2.8 years old) was even worse than yours! He was a fun, and loving kid but one day he just did not want to do things we asked him to do. He screamed, threw things, hit, and bit.

I tried reasoning with him, sitting and looking into his eyes, told him how I felt and what should be done, bla bla...all the golden rules you should do with kids but nothing worked!
We were on vacation last week, and he was so not himself that I did not know what to do with him anymore. I spent one of my vacation nights searching for a book, and found 1-2-3 Magic by Thomas Phelan. I used the 123 counting with him, and voila! It works! I only have to count to 2 to get him to stop doing things we don't want him to do. Well, having said that, he still tries to test my boundary but I feel more calm, and in control of the situation. I am so pleased and love spending time with my son even more.
I even use the tricks from the book to wean co sleeping and it has worked like "magic" for 3 nights in a row.
