Afraid of sex..

I am 4 months pp and still haven't had sex with my husband. I was cleared by my OB at my 6 weeks pp appt. I just haven't really been in the mood. All my energy goes into my daughter and I don't feel like a wife anymore. I don't feel after all the bodily changes that I am attractive or functional, if that makes sense. I'm attracted to my husband, always have been. But the thought of sex gives me anxiety and doubt that it will satisfy him like it used to. He tries to have sex with me but I can never go through with it. It's almost like my body is in a knee jerk reaction mode to resist any contact in my vaginal area. It's like I feel as though my body is only to be used as a mother and not a spouse. Does that make any sense at all? I feel like I'm going insane. Can anyone lend some advice or experience?