signs of infection down there!?

or i could i be pregnant? i was supposed to have my period on the 18th, i felt a gush like as if it was my period. i went to check and it was only some yellowish, white discharge. had unprotected sex on the 15th. had it again on the 21st. yesterday, the 24th, i felt a gush again, i thought it was finally my period, went to check, and it just looks like i peed on my underwear. which isnt pee 100%. its like when my water broke during labor. i am 3 mths post partum. is this a sign of an infection? never experienced this before wout being pregnant.