I am so sorry this is happening to you.
There are a lot of myths about virginity, and one is that someone can determine virginity by the presence of a hymen. This is a thin membrane that's located at the opening of the vagina.
There are a lot of variations in the hymen from woman to woman, and some women don't even have one. It can be a bit of tissue that doesn't actually "close" the opening, or be broken or torn easily, by using tampons, exercising, normal activities and you may never feel it.
So, no, there is no way to tell for sure that you aren't a virgin unless you tell someone. If your safety will be at risk if someone finds out, please don't tell anyone.
I wish you the best.