Stress is never good on your body, pregnant or not, but especially when you are pregnant, you need to try and minimize any stress that you might have. Try to replace the bad stress w/ good thoughts, positive talk and the reality that everything will be okay. Keep the thought, "I care about the baby and am thinking about him/her". Second move forward in your life. Begin to slowly organize your life + how you want life to be with the baby when the baby arrives.
There now is information to indicate that stress can cause the body to produce certain hormones that can perhaps cause miscarriage and that very likely can bring on preterm labor.
I know all of this is easier said than done. Just take it one step at a time and find a support group to keep your thoughts positive and your stress low. Find this with, your friends, a family member, a family pet, a distant relative, an online community (there are tons out there) or with your significant other.
I will keep you and your situation in my thoughts and prayers. Good luck to you.
Proud mommy of a 15 month old little boy!