exercising after complications

Crystal
So when I was about 11 weeks I had a gush of blood without cramping followed by some light bleeding for a few days after. Went to the ER and thankfully baby was fine and there was no explanation for the bleeding. My dr never seemed concerned either. I really want to exercise (nothing crazy) to stay healthy and somewhat fit during the remainder of my pregnancy. I am currently 20 weeks. Anyone have any feedback or thoughts?