I had a similar experience with the drug Cymbalta.

I think I tend to use orgasms as a way to relieve anxiety, so I kept trying. The difference was I found it much harder to actually reach an orgasm. After about two weeks the side effects went away, and then of course we changed the dosage.

It's been several months since I started on it, but I can say it was worth the trouble. The side effects have become non-existent and I find myself feeling much better about life. Talk to your doctor about it but don't get discouraged with the bumps on the road.