I think the correct term is "uterine prolapse" or something of that nature, and it's fairly common, especially as you age and after childbirth. Basically, the muscles and ligaments that keep your uterus in place can get damaged over time, with the net result that your uterus slides down into your vaginal canal.

I think that your doctor can fit you with a pessary to keep your uterus in where it should be. I don't know of any other real treatments. (My doctor-sister once heard about a lady who used an intact sweet potato as a pessary, forgot about it, and was then horrified when it started to sprout. I don't know how true that is, but I don't think that produce is the appropriate way to treat this!)