D.B.
From all your posts, you seem quite overwhelmed by this baby. You have exclusively breastfed for a long time, and that takes a toll on any woman, even if she's philosophically in favor of it. Weaning is hard, and so is having an underweight baby (as you discussed in prior posts). It's normal to just be so totally sick of the crying. And it doesn't mean you don't love your baby - it means there are stresses and strains of raising a child. There are times when we are so sick of our kids, and that can happen at 2 weeks, 12 months, and 12 years.
The issue for me is that you want to hurt him, or just let him do his thing without intervening if he's upset. That doesn't mean there's anything wrong with making a child this age wait a few minutes until you are free, or letting him try to settle himself down without racing to his side with every peep or crying jag.
But that is not what you are talking about. You are more than tired, overwhelmed or depressed. It's time for intervention. Please do at least one of the following tomorrow: call your baby's pediatrician, your primary care doctor, or your obstetrician/gynecologist, and say very simply: "I need help. I often think about hurting my baby. I need to see someone immediately." Whoever you get through to first should be able to help you. You must act immediately - wanting to hurt your child is something that can and must be treated. You are not alone, but you cannot manage this alone either.