Scared of pregnancy

I had my first child 7 weeks ago. I’ve been physically ready to resume sex since 2 weeks PP but mentally?? Not so much. I am petrified of getting pregnant again, I don’t want more kids. Ever. I’m getting Merena soon but I’m still 100% scared of this happening (I got pregnant on birth control) has anyone else had this fear? How do I get over it? I desperately want to have sex with my husband but I can’t bring myself to get close to him. Will this fear go away with time? Is there any steps to help?

*I am breast feeding and my cycle has not yet returned. This fear is causing issues because I’ve been distancing myself from him because I can’t handle being touched by him because I want him so badly but I’m afraid of sex now.*