Have you seen or spoke with a doctor/gynecologist about this? If not, you should.
Everyone is a little different, not all hymens look the same, and there are different 'types'. You may have an imperforate hymen, which means your hymen completely covers the vaginal opening. You can look it up and research 'imperforate hymen' online, to see if it matches the description of what you have. If you think you match the description, you must make an appointment to be examined by a doctor for further help.
I'm so glad you were able to find the info. you were looking for :)
Good luck w/ your appointment!