getting only foremilk?

I googled last night baby poop - something I never bought I would do lol. But my 5 week old has had a few days of bright green poop- multiple sites said that's due to baby only getting foremilk and not the fatty stuff behind. If my baby only nurses for about 10 minutes, how do I insure she's getting the hidmilk? I had no idea how much foremilk I have.... I usually leave her on one boob (that was recommended as well so she gets he hidmilk) but around 7-10 minutes she hnltches herself and we burp then sometimes she won't take anymore... any help?