Second thoughts. Long

First if all, I am 23 years old and have been married for 3 years. For the past year my husband had really wanted a child and for us to get pregnant. I did get pregnant last year, but had a missed miscarriage and a D&C in December... And now he wants to try again, disagreeing to use protection. And me... I am agreeing with him... But I am afraid. So many factors come into this. I know what it's like to be around kids, I know it's pretty much putting your life on the altar. I have little kids in my family (nephews and so on) and I love them dearly, but they are a lot of work. Sometimes I feel like I need a little more time... For me, for us. I am afraid for my figure, something I worked really hard for and which is nearly perfect for me right now. I am afraid I won't get it back after childbirth. I had an eating disorder too (which no one knows about...), so that's s factor. I am afraid I won't be the best mother. And most of all I am afraid of another miscarriage... Don't get me wrong, if I fall pregnant now, I will do anything to have that child and I will love him or her... But I am scared. I am not getting any younger too and my husband has every quality I would wish for my child's father, he is literally the best and most worthy man I have ever met. My point is: am I a horrible mother to be? Am I being selfish?...