I've been baking oatmeal raisin cookies with my mom my entire life and yet for some reason, I ended up accidently buying (and then using, because I didn't feel like going back to the store lol...) the quick oats. I had the problem you're describing now. The texture is just not the same as using regular oats, they're gooey and just don't set up right. Oh, and they ended up with bubbles while cooking. Try regular oats and I bet you won't have a problem.