Welcome to SR Nohope. I understand your fear, been there and done that twice! When I was pregnant with my first child I didn't want to stop what I was doing. I kept drinking and drugging. At about 7 months I got scared for some reason and went to the dr and told him what I had been doing. By the grace of God, she came out ok. Should of learned there. Did the same with the second because the first was ok. This time my son has some learning problems but nothing to drastically alter his quality of life. I feel very lucky. Still to this day I feel guilty but I had to move on.
Don't create the worst case to happen for you. Go to the doctor and tell him what you have been doing and take it from there. You may be worrying about something that hasn't happened. Good luck and we are here for you.