Late for period and have white/clear discharge that is running down my legs what could be the cause?

If you had sex since your last period, you could be pregnant. Do a home pregnancy test. If the result is negative repeat the test in 4-5 days. Use first morning urine and follow instructions for the test carefully. If you do not wish to be pregnant, use contraception all the time, every time. You may consider implanted contraceptive, or IUD. Wish you good health!