I have placenta previa, it was seen at my 20 week ultrasound. I was put on lifting restrictions and pelvic rest. A huge concern for you now is bleeding, that is excellent that you are already 32 weeks and have not bled!
My first bleed was at 24 weeks, I've been on hospital bedrest ever since (30w5d today) and I have had 4 bleeds. I have had quite a few ultrasounds, my last one being this past tuesday baby measured 4lbs5oz but I also have GD.
Just take it easy until you see your doctor it may just be a partial previa which is better than a complete. Again it's great that you havn't bled yet and you are already 32 weeks!