I got this after I had my daughter, your best bet is to speak to your doctor. They will understand I promise! Don't feel bad or beat yourself up over it, it's extremely common and there are many ways to help with it. I ended up getting antidepressants and was told to excercise and make sure I got plenty of me time. Trust me go to your doctor they can help you
Oh sweetie, it is so common to feel this way. Don't be ashamed, your making a huge transition into mommy whilst recovering from a major event and having to be a carer to a demanding baby. Let your dr know so that he can give you some tips and connect you with some support. In my area you can go to mothers groups with moms who have similar experiences which we really helps to talk to other moms without the pressure of pretending all is great. Good luck!
Exercise can help out a lot! I would just talk to your doctor, they are used to this kind of stuff and if it is bad it is better to get help.