As as single mother of a 5 year old precious girl with virtually no help from the father (emotional or financial), I can definitely relate to the frustration. But in my experience as a mother (and in my 4th year of my social work BA), I can definitely say that, although your anger may be warranted, make sure you NEVER take it out on your son. He did nothing to warrant it; he's expected to act this way at age 1, especially if there is a new baby at home. Please don't think it's intentional, he's only 1!
My theory is that children are never born yelling, screaming, tantrums, etc. If they are acting this way, they're either not receiving enough attention or the family dynamics are unhealthy, neglect, abuse etc. Generally speaking, children react badly to a bad situation.
I suggest you get hold of a therapist asap to help release your emotions in a healthy way and to acquire healthy tools in parenting your children without the use of anger or violence. A therapist may refer you to a psychiatrist to determine if medication is needed in the event of anxiety, or depression or any other mental disorder.
Personally, whenever I'm going through something horrible and not feeling well, I always overcompensate by making sure my daughter is completely UNAWARE that mommy is nervous or feeling down etc. And I make sure her routine is never disrupted on account of me. A child's wellbeing and happiness always need to be prioritized before your own.
On a personal note, when I was going through my divorce 3 years ago, I became severely depressed, lost 25 lbs, and didn't socialize with anybody. (I've suffered from depression since I was a kid but was only diagnosed at age 22 when seeking help). The divorce triggered a severe episode of depression in which I was struggling to care for my daughter and be the best mother I could be. Even going through this hell, I still made my daughter a priority regardless of how difficult it was. Getting help was the best thing I've ever done, and though I still experience ups and downs, I'm a long way from where I've come It's important to recognize when to get help.