I agree with Wondergirl, you should be worried at this point. A guy doesn't have to ejaculate for you to get pregnant. There are plenty of sperm in the early pre-ejaculate fluids that can cause pregnancy.
You can take a test using first morning urine to find out whether or not you are pregnant. However, you should test again next month around when your period is due.
Are you prepared to tell your parents that they are going to be grandparents? That will happen if you continue having sex this way.
Using multiple forms of birth control is recommended, but is still not always 100% effective.