It is natural for you to feel resentful when your child is giving you such a difficult time, and you have two of them under age three to manage. My first thought is to wonder if you are getting enough time to rest and take a break from your son. If you are frazzled, you are not going to be able to parent the way you want to, because you are only human. It is a great idea to lean on your husband, friends and relatives to make sure you have time to re-charge.
Normal behavior in three year olds does include lots of shifts in mood, from ecstasy to the depths of despair, to rage. You have an extra complication in that you do not know exactly how much he is able to communicate with you and understand what you say to him. I am glad he is getting speech services, but I wonder if he is getting enough? Sometimes kids get only a 1/2 hour each week, so it may be wise to ask the early intervention team to revisit how much therapy he needs to make progress (see the website of the American Speech Language and Hearing Association www.asha.org to learn more). I saw that you have had autism ruled-out, but you did not say how this was done. Since you did not mention psychological testing, I am going to assume that a good comprehensive evaluation by a psychologist or neuropsychologist has not been done.
From what you are reporting, a lot of different things could be going on with your son. I am guessing that you are having trouble planning interventions and setting expectations because you do not have enough information about his abilities, strengths and the extent of his weaknesses. An in-depth developmental evaluation will tell you what you need to help him at home, school and in social settings. You especially need to know how well he understands what you say to him (receptive language). It may be an auditory processing disorder, but you won't know until you have him evaluated. Talk to your pediatrician for a referral. You can also read my Medhelp article on developmental testing.
You may also want to work with a psychologist to learn how to manage his behavior. I see a lot of children this age because age three is a very tough year. Your best bet will be to work with a psychologist who can provide you with Parent Managaement Training, Parent Effectiveness Training, or who can teach you behavior modification techniques. You can learn to help him develop more self control through positive means with very little punishment. Distraction does work sometimes, but it does not solve the problem or do much to improve the situation in the long-term (as you have already observed).
The good news is that children this age respond very well to positive behavior plans, and with the help of a good therapist you should see improvement in a few weeks. In the interim, I recommend the book The Kazdin Method by Dr. Alan Kazdin. Its a very practical guide to teaching kids to engage in desirbale behaviors instead of problematic behaviors. I also recommend Your Child's Growing Mind by Dr. Jane Healy, which will give you lots of information about how children's abilities and emotions develop over time.
Disclaimer: This Medhelp post is written for informational purposes only. It is never intended to replace face-to-face psychological or medical care. This Medhelp post is not intended to create a patient-clinician relationship, nor to give or rule-out a diagnosis.
Thanks so much for your time. I will follow up on your suggestions.