That makes sense. She needs to see her doctor and discuss the pregnancy.
3 weeks pregnant? Most women do not find out they are pregnant till they miss there period. There really is not such thing as being 3 weeks pregnant. It takes 6-10 days just for the egg to implant into the uterus. She would have to speak to her doctor about exercises to determine if she is high risk or not. If she is high risk, then no exercise except for the normal walking around. If she is only 3 weeks pregnant, then why did she stop metformin? For those who have pcos, metformin can be taken up to either the 12th or 19th weeks in pregnanacy as it reduces the chances of m/c.
Like I said before, we are not doctors here...we can only give opinons, but all in all a doctor should be seen.