Oophorectomy leads to early menopause?

I had my right ovary removed 5 years ago, in my 20's and was told it wouldn't effect my chances of getting pregnant. Now I am in my early 30's and have been trying to conceive with no luck. My doctor ran some blood tests and he says I may be facing early menopause, although I am getting a regular period. He is giving me another test called chlomid challenge test to help determine my results. I'm freaked out because I think I am to young for menopause!!