House breaking

I have a 12 week old goldendoodle puppy, we got her when she was 6 weeks old. she was shy and timid as most puppies are for the first few days, I have had her to the vet twice for check ups since we got her, my issue is house training, for the first four weeks she seemed to do very well, but lately it has been very trying, she is crated during the day and for bed time, she does not urinate at all in her crate, we let her out as soon as we arrive home and awake, she will pee but from that point on she will pee approx every 15min in the house with no warning. I need advice how to break this it is getting very frustrating, I have tried positive reward, scolding it seems she just does not care. Help I love her but can not have her ruin my whole house and do not want to keep her crated all the time that is not fair.
   

Before you can get this problem under control it's best not to let her have free run of the house. It's best to keep her away from area with carpet using baby gates.
   
If she has urinated on carpet I would use Natures Miracle to remove all of the scent or she will be drawn back to it. There are many products on the market but it is the only one I have found that works.
   
Perhaps part of the problem is after holding for so long in her crate she can not go outside one time and completely empty her bladder. Since she goes again 30 minutes later take her back out a few minutes before that. Wait until she's just finishing and praise her. Scolding her for going inside will only make matters worse. If you catch her going inside, make a sound to distract her and take her outside.
   
We were taught in dog training class that a puppy should be able to hold it for one hour every month they are plus one. So she should be able to hold it for four hours. That's why I mentioned she may have to go so frequently if she stays in her crate longer. Normally I would suggest having your vet look at her however since she can hold it in the crate without a problem I don't think it's a medical issue.
   
I recommend the ASPCA's website for all behavioral issues. They have excellent advice that is very detailed.
   
Hang in there and good luck!