When i first started oil pulling, I felt amazing, but within a week or so i started feeling tired and really sluggish. I think it was the die off effect of whatever needed to die off:) I took large doses of Vitamin C - and it help me enormously. I didn't want to stop pulling - I was already hooked:)
Hopefully you will be fine - don't rush the oregano, the coconut is powerful on its own and enough to cause a die off. Doing too much too early may overwhelm your body. But for the future, it is a nice oil to add to your pulling, a few drops at a time, leaves your mouth feeling even nicer (even though it has a pizza tones to it, LOL)
And congratulate yourself on doing OP. it is the cheapest, easiest and most powerful technique to detox. I have so much more energy and my skin looks so smooth... A truly life transforming tool:)
Keep us informed on your progress...