I hope this is a short phase!

I never thought the day would come when my sweet, adorable son hit me and yelled, "I don't like you"! Well, the day came, and has repeated itself at least 3 more times! It breaks my heart and I just don't know what to do. I have always tried to be consistent, but I think the guilt of not being with him as much as I'd like, has eventually gotten to me and caused me to allow him to be spoiled rotten. Now, there is a difference between spoiled by Grandparents (as all children are) and spoiled rotten. Avery is so spoiled these days that HE STINKS. (and so does his attitude) Of course he can be so sweet most of the time, but when he gets punished or doesn't get his way, the different story begins. Please pray for me and my patience as a mother. I need to get this phase (please be a phase, please!) under control before preschool starts in a month, and definitely before the new baby comes in February! Surely it won't last that long, right?! I'm trying to figure out if I've made a mistake with spanking b/c it just doesn't make too much sense to "pop" him after he has hit someone else, but "time-out" just doesn't seem to be enough right now. I'm lost and begging for suggestions. I just want my angel back for good!