In a case like this I would suggest that you have an ultrasound to see what kind of health the baby is in.
If you have decided to continue with the pregnancy start taking B vitamins and at least 1mg of folic acid per day. Also look at taking Red Raspberry leaf in tea or decoction form.
Do you have someone close to you that you trust with your life? A friend that has not motives? If so turn to that person for help and support.
Please also seek out a Crisis Pregnancy Centre - there you will find love, support and hope. They will point you to all sorts of resources to help you in your time of need.
Please remember that no matter the decision that you make, it will affect the rest of your life. Think things through, and give yourself time!
If you ever need to talk please feel free to email me.