what are these symptoms of? am i pregnant

hey so, i had sex on nov 15 or 16th i experienced light headaches,back pains, and lower ab pains, then i started my period on the 19th it started off very light, and then it got very heavy with clots and lasted for about 6 1/2 days when it usually lasts 4. i took 3 preg tests and they came out neg. and after my period i started feeling heavier cramping, and then i had sex again on nov 30th and during sex i started excreting milky,sticky,light/no odor discharge, wayyy more than normal, and i went to the doctor today, they said iwasnt preg and they didnt know if i had an infection or not because nothing else was wrong with me besides they saw white cells in my urine which may be because i wiped wrong before doing the test. no im on 4 types of antibiotics can anyone help me? i really want to have a baby.