Baby go or baby no

My boyfriend and I have been together for four years. He is a butcher and I am currently in college and working at the college part time. We are planning on getting married soon and also buying a home. Two years ago we lost a baby when I was four monghs pregnant. We were young and very unprepared, now that we have moved on he wants to try again soon, but I feel as if I don't want to try again. I don't want to risk loosing another baby. What do I do?