Irritability and wanting to cry all the time, especially when you know both are irrational, are signs of depression. Take it from someone who has dealt with clinical depression since I was a child, it doesn't always take the form of sadness. You need to go talk to your doctor, tell them everything, like Dawn said, and try a whole-life approach. In other words, make sure you are getting out of the house every day***, that you are eating right, that the stresses in your life are minimized during this time. Take meds for a while if you need them to get through this phase.
Don't worry about your husband, he's doing what he can to help, he just doesn't know what else to do. Do you need more time to yourself? Tell him you need to get out more when he is home, and have him take care of the baby without calling you a million times to ask questions about it***. Go to the doctor and ask THEM how your husband can help more. Better yet, bring him to the appointment and have to doc tell him. Men like to do "concrete" things to help, they aren't always good for a shoulder to cry on, they need to actually DO something and SOLVE the problem. Your husband is confused because this isn't something he can solve.
That all said, you are also still grieving the loss of your father. Read about the five stages of grief by E. Kubler-Ross, and understand that you have to go through all of the stages before you see the other side of it.
Much love to you. You are not crazy, you are depressed. It's ok to ask for help.
***eta
I gave you bad advice in encouraging you to get out more. Kinda slipped past me that you were only 20 days PP. So, instead of getting out of the house, GO REST without the baby, give him to your husband and tell HIM to take the baby out for a bit. Then when you are feeling stronger, get out for regular walks. But for now, you need rest. All the old ladies told me, when I had my first, that I shouldn't even leave the house for 40 days. They had a point. You have a long and winding road ahead of you raising this child. Rest now, you're gonna need it! Really! It's gonna be OK! :)