First time mummy

Hi mummies, I'm a mummy to be and I'm constantly worry about 101 things. Whether my baby will healthy, did I eat before for my baby, does baby have enough nutrition, will baby have down syndrome or other illness. I'm so worried and my husband always say I worry too much and think too much. But I'm just very worry and want the best for my baby and I'm afraid my emotions will effect me. #pleasehelp #advicepls