"I might have a miscarriage (again)."
Miscarriage is something that can happen. As much as 20 percent of all pregnancies ends in miscarriage. This risk goes down significantly after the 12th week of pregnancy, so many women feel able to relax once the first trimester is over and done with. Unfortunately, there is little you can do to prevent miscarriage. Women who suffered multiple miscarriages are more likely to be really worried it will happen again.
"I am afraid my baby will not be healthy."
Thankfully, prenatal care like screenings, tests, and ultrasounds can catch many conditions. Persistent feelings that there is a health problem with your baby should probably be addressed with prenatal tests. These can either settle your fears, or let you know there is a real issue.
"I got drunk/smoked before I found out I was pregnant and I fear for my baby's health."
You are by no means alone. Talk to your doctor to find out what the real risks are, and to do early prenatal testing if you are really worried. While smoking or getting drunk is not something a pregnant woman should ever do knowingly, quite a few ladies did these things before they found out that they were expecting a baby. Most of the time, your baby will be just fine. Of course, fear can be a very powerful and useful emotion. Together with physical symptoms, it can alarm you that there is something wrong, and you need medical help. It's up to you to decide whether your fear is a general one, or that your feelings are caused by knowing there is actually something wrong. In either cases, talking with your doctor or midwife about your specific fears can help you ease your mind and either let go of your fear, or confirm there is something that needs to be addressed.