I'm so sorry that you are feeling this way. :( I have totally been there. Im currently on Zoloft, but I still have horrible anxiety and terrible mood swings. I love my daughter and husband to death, but sometimes I just need a break. I need a little "me" time. Every single day is so difficult and exhausting. Taking care of a baby is so much stressful and mentally exhausting.
If I was you I would book a massage, yoga class, or exercise class to help you relax. Also, don't be afraid to ask DH to watch the baby and let you take a bubble bath or read a book alone.
If nothing else helps you might want to consider talking to a therapist. Sometimes they are great for teaching relaxation skills and meditation.