If your baby is only 5 months old, please keep in mind, having a baby changes your life and sometimes it is hard to adapt. I am in no way trying to stick up for him, but I have been through it 10 years ago. How is communication with your husband? Can you do marriage counseling?
If you leave with your baby, it is NOT considered kidnapping. Maybe you and your baby could go stay with a family member while you and him try to works things out. If he is not willing to talk and work it out, then divorce him.
I have been a single mom for 10 years and it is not easy. Not for me or my son. I suggest giving it some more time and see what happens. But try to work it out first...it might make a difference.
Either way, good luck, and always, always protect your child.
Attempting suicide is NOT illegal. It will get you sent to a mental hospital for observation and treatment for the reason you wanted to commit suicide, but no one has ever been sent to prison for attempting suicide, and no state has any laws on the books about it.
Self injury would be treated the same way. The person would be admitted to a mental hospital and treated for their condition.