Orthodox Christianity believes very much in magick, they just do not call it that. Usually the magick is that of using religious figures to carry out their desires through prayer and symbolism. Much of it is sympathetic magick.
For instance the use of religious medals as amulets and the act of kissing them. They aren't kissing an object but showing reverence and love. Crossing themselves not once but three times (3 is a very powerful number of divinity). Using color and objects as representations of sacred significance. Prayer is done through meditation which can even lead to trance when performing the rosary the proper way while focusing on one's wish. Instead of stating "I bless" "I heal" "I protect" they choose the name of the "holy" figure they feel will do the job. "God bless" "Jesus protect you" "Mary heal and comfort you" etc. The will, the belief, and the focus is still there. The only difference is, the person speaking becomes a middle man of higher power. This is seen in a lot of magick, especially that of Native American shamanism where the shaman will provoke certain spirits to come through symbolism and prayer and then work with them to create the results. The person is the middle man, not the directly effecting factor.
This is actually why I sought out witchcraft when being brought up around Cherokee and Christian family members. I did not like feeling like I could do nothing without help, and liked how witchcraft empowered the self, with the option to include other beings for aid but not the requirement.
Here is what I wrote a few days ago about the basic idea behind why magick works. Perhaps it will help you to gain a peace of mind over your predicament.
"Most magickal practioners of past and present believe one specific thing. Everything in the world originated from a single source and the energy of that single source connects us to all things. Each individual is a part of the whole. We effect it each and every day. This leads into cause and effect (which goes by many names). What we do is a ripple in the water or a vibration on a strand of the web."
So in essence, what we do, the energy we use, is connected with everything, including the source (in your case "God"). Some choose to pinpoint certain parts of nature or certain beings to connect with. Others go straight to the center (God, Goddess etc). And still others merely use the connection to those they personally contact to effect their surroundings through association. Some use all three ways. Regardless, it is all still the same web of life, and we all use it. It's just a matter of opinion as to which is the right way and of course style.