Tried Neti Pot now congestion is worse and a headache!?

I was desperate for relief earlier so I tried out the Neti Pot with a saline solution. It took a really long time before it started coming out the other side, then it was only just drips, so I wonder if Im too congested for it? I had streams of yellow gunk come out *Sorry!* but about 5 minutes later I was just as congested plus my face feels like it will explode and now I have a major sinus headache to boot. What did I do wrong? I used a premade saline so I know that it wasn't that....and how do I get it to go away?