Don't ask for Prozac. Find a psychiatrist and let him/her decide which med is best for you. Prozac is the oldest SSRI and there are better meds since it came out.

Get to the specialist right away. You have your son who needs you in a safe mindset. Thinking you can think your way out of these aberrant thoughts is how babies get hurt. Asking for help is a sign of maturity.

Call someone and tell them, "I have suffered a brain injury and sometimes I get these disturbing thoughts that scare me. I don't want to be a risk to myself or my baby so can you get me to some help?"

Try calling Clark County Mental Health. They have programs for just this kind of situation.

My best to you.