Ligonier Ministries has free resources for study and I just found a great free resource that is related to the area of study here at 'Reformed Seth,' that is, the Trinity. R.C. has a series called, "The Mystery of the Trinity" which can be viewed for free here, and the free study guide can be found here. You can save the study guide to your computer so you can study it anytime you want, instead of going to Ligonier's website each time you want to study it.
The video series has six lectures, the study guide goes right onlong with the lectures, so you can bring up the video lectures and use your study guide along with them to have a good study of the Trinity. Whether it answers questions, or brings up more questions, you'll definitely be thinking more openly about the Trinity.
For more R.C. Sproul resources click here.
Walter Martin's short defense of the Trinity here.
John Macarthur on the Trinity here.