Sorry I'm so late replying to this, but my sister (now gone) had a problem in the early 80's, similar to what you describe.
One morning, while making breakfast, she dropped flat on the kitchen floor, unconscious. Fortunately, her husband was still there, and called an ambulance. She had a fetus developing in one of her falopean (?) tubes, and the tube burst. The instant pain is what caused her to pass out.
The tube had to be removed, which lessened her chances of getting pregnant again by 50%, but other than that, she was fine.
She was pregnant in less than a year, and brought a third son to the family.
My thoughts and prayers are with you, and keep us posted.