Scared

I miscarried in january, and I always told my self I wanted to wait to get pregnant again, well today i took two tests and I am pregnant, and I want to be excited I really do, but I am so scared that im going to loose this one to, and all my husband keeps saying is not to think like that, that this one will be the one but I dont want to get my hopes up. Its like im already preparing my self for the heart break. I already want to call my dr to have them start watching my hcg levels. I know that it wouldnt be any good for me to do that, but I am so scared.