i second the coconut oil, it's the only type i have used for oil pulling and i have never had a hard time (i.e., with the taste, no gagging) and it actually WORKED to improve my oral health. i've been pulling for 5 months, and at my last dentist visit i had "no tartar, very little plaque". this is the first time i have ever heard those words from my dentist.
also, two weeks is just a start. people who do this successfully have adopted a lifestyle change, not a two week stint.
Try a different oil, and commit to at least a month, or more depending upon the health benefits you are seeking, and your current oral health status.