Postpartum Depression & PTSD

I feel like the most terrible person on this planet. my daughter is 1year old with CHD ( congenital heart defect). Just last night I was lying with her in bed when suddenly the most dispicibal thought entered my head. This thought was so horrid in my opinion that it sounded like a completely different person. my daughter the the happiest for a little girl who has had open heart surgery at 8months and has more ahead with a pacemaker. This thought had me terrified as it made me feel like I wished her death. I would never wish that on my beautiful daughter that I would give my life up for her safety and well being. This feeling has left me reeling and I don't feel normal. I didn't suffer postpartum depression after birth, but when my daughter was diagnosed and operated on I went through PTSD. I am not expecting anyone to understand I just need opinions I love my daughter. and don't want anything bad to happen.