Of course you love him, it is ok to get irritated! If you did not, you would never be able to mold your children into the great humans they are going to be. You would just take the valium and let them raise themselves!
As I have told other moms on this site regarding behavior that frequently is out of order, I have a very different stance than most everyone, but my kids, my 2 nephews, and my goddaughter all did about faces with their behavior when the food was changed. You can try all the behavior modification consistencies and I am sure they will either work some or all. Your son is showing low impulse control if the consistent discipline does not work. Hitting is a outward display of lack of control or power. It is not ok to hit and you need to be clear with him about that, however, you also need to look for what is he struggling with as to why he responds consistently with aggression instead of attempted words or non-verbal gestures as to what he is trying to do. Even a 14 month old should be able to do that do that. If he does not gesture or use non-verbal communication by this age, I would see one of the specialist at www.floortimeatlanta.com for an evaluation.
If you want another take, assume your son, like many kids I know, are responding to their bodies not being regulated and their tummies are out of sorts. Food sensitivities and allergies will cause big problems for their level of tolerance. No, they don't tell you that either. Futher, they often crave the foods that are the most problematic.
Removing foods that naturally are hard to digest and thus can cause inflamation is the first step to see if the behaviors improve.
First, remove milk (substitute rice or almond) and all milk products. Two weeks later, begin phasing out wheat. Usually, this behavior is more related to the wheat, but milk is the first and easiest step. Be sure to notice what frequency the behavior occurs now and what frequency happens within 2 weeks of the removal of milk and 1 month from the time wheat is removed. No calcium is not a problem, rice milk is equal to cows milk in the health regard.
There is lots more health work you can do to improve behavior, but usually, you will see an very nice improvement in behaviors with just this. Do not tie the change of foods to the behavior, though, it will back lash on you. Just say it is to get her tummy better.
Just my 2 cents, J.