Re: something protruding from my vagina
More than likely it is your bladder that is prolapsed(falling down)That you are seeing. The bladder is below the Uterus, and as "niknak" mentioned the uterus can also prolaps, and put added pressure on your bladder. I agree with niknak, you could see your GYN, they would be able to tell if either or both were prolapsed.
Both my Uterus and bladder were prolapsed back in the 90's and I had a hysterectomy/bladder sling surgery to repair it.
Wish you the best,