OB/GYN can’t find my left ovary????

Today I had my first ever Transvaginal ultrasound as we are starting down the fertility treatment route after TTC for three years. The OB/GYN said my right ovary looked perfect and she had no concerns but she couldn’t find my left ovary?? She didn’t seem concerned and just shrugged it off saying “you only need one!” but it definitely has me worried! Naturally I googled if anyone had the same experience and it’s got a lot of mixed responses which have me even more worried! Have any of you experienced this? And if so what was the outcome?