What Causes White Discharge Before Menstruation?

i have gooey vaginal discharge for about a week in between my periods. the last time i had unprotected sex was about 2 years ago and it didn't start until about 4 months ago. it is only for that week. i'm clear for a week after my period and for most of the week before my period. i've always had increased discharge for that week but it just recently started being gooey. everybody tells me this is mostly normal. sometimes it's a little bit of a yellowish tint but thats only when i peed before i wiped. if i wipe first it's always more clear. so i think it's just because my pee got on it. so is this normal?