The majority of my pregnancy I was crying and stressing on a daily basis. My son is just fine. HOWEVER if you stress too much it can put you in early labor. I dont know what is stressing you but try to not think about it and try to be calm. Good luck with everything.
Stress and tears come along with just about every pregnancy. It really doesnt have an effect on the baby unless it becomes depression. I wouldnt worry but if you are too worried about it talk to your doctor about relaxation techniques such as taking a warm (not hot) bath.