From what I understand, endometriosis is a condition where the endometrium (the tissue covering the uterus) begins to grow in places it shouldn't (such as the fallopian tubes). The endometrium in the fallopian tubes responds to hormones in the same way as that of the uterus and so swells and thickens before being shed at the end of the cycle. However, in the fallopian tubes, the blood excess blood can cause inflammation that can lead to scarring. This scar tissue in the fallopian tubes is what can cause infertility. In this case, I would strongly advise that you get diagnosed and treated asap as the longer you leave it the worse the scar tissue could become and hence the higher the chance of infertility.
BTW, even in the worse case scenario there are several 'Assisted Reproductive Techniques' available that can 'bypass' the problem of blocked or damaged fallopian tubes and still enable you to concieve in later life.