You have to set them up for success if you fail to do that than they are going to fail and its your fault. and Yelling NO and grabbing her by the scruff of her neck is only going to hurt and make her scared of you no good will come from that
, thats probably why she kept peeing she was scared...and if you make your dog scared of you she will never come to you for anything and will start hiding her potty accidents...It has to be a positive correction... when she does it in front of you say NO to her in a firm but calm voice and pick her up gently not by the scruff of her neck and take her to where you want her to potty, outside or on a potty pad and tell her go potty and pet her at the same time than take her and put her in her crate/xpen play yard and leave her for about 15 minutes or until its time to go out and potty again. You said she was never train right in the first place so you have to start from the begining with her as if she was a puppy....keeping her confined, taking her out every 2 hours, taking her out after she eats, sleeps, plays just like a puppy...don't give her a chance to have an accident and 6 weeks really is that long no dog will be pottied trained in that time frame, it takes months...setting them up for success is the key and that starts with you!!!