Was your surgery recent? I have heard of a handful of cases where the surgeon could not find an ovary during surgery. And I know of cases where ovaries could not be seen on imaging (e.g., ultrasound). So it is possible that you still have an ovary.
It's a shame that your surgeon didn't remove just the cyst (cystectomy) since our ovaries are critical to many aspects of health our whole lives. However, gynecologists frequently remove ovaries unnecessarily so it's not surprising.
The symptoms of ovary removal are usually severe. They were for me. And it increases the risk of a number of health problems too. Removal of one ovary can be just as severe and has also been shown to increase risk for some health problems.
I hope this helps. I wish you the best moving forward.
I know someone who was born with only one kidney, so yes, you can be born with one ovary. If it's really not there, not hiding somewhere he couldn't see it, then you have no ovaries now and are going to go through surgical menopause. That could be tough. You might consider hormone replacement therapy.