Concentration during sex.

Concentration during sex.

I have been this problem after our second month of marriage, it's so hard for me to be concentrate during sex. I don't see that problem in my husband, I can feel and see that he really enjoys the moment, but for me is not that easy, I'm start thinking in a lot of things, for example I think that I'm winning weight, that my hair is falling out a lot (truth) or what I'm going to do after sex, sometimes I say to myself that I need to be concentrate, that I need to enjoy more my time with my husband but that didn't work, we don't have kids and I don't work, so I don't know what do to.

Anyone have some advice? Thanks