Don't want to stick in my two cents before you hear from other more qualified women, but since no one has chimed in as yet, I'll share with you my insights:
Your method of birth control, and its libido-inhibiting effects, should be switched, if possible. Your body already has to deal with depression and all of its complications so the IUD will only diminish the libido further.
Wellbutrin should not cause a decrease in libido as much as other antidepressants, but it also isn't as effective as an antidepressant which could mean that the depression itself is not suppressed enough for you to want sex.
Press your doctor for other birth control and depression management options as far as medication is concerned! Also, do remember some of the best natural therapies which include lots of physical exercise, fresh air, nature, meditation, eating well, plenty of rest and water, maintaining a close and loving relationship with your spouse, etc.
Two months is too soon to give up on a great sexual relationship in your marriage!
Oh, and another thing. Because you're inexperienced sexually, you have to remember that a clitoral orgasm is very different from a vaginal orgasm or a G-spot orgasm! If you're used to "pleasuring yourself" you might be dismayed to find that real sex with a partner will take more time and effort to get to the O. But that should be part of the fun, right?