Unexplained infertility rant

Just a little whinge... I'm on day 4 of a rather light period. I know I'm not pregnant, I've never been pregnant, never had a positive test and give sort of given up but there's constantly that little speck of hope of "what if..?" I can't even find peace in having a period! Because what if... its implantation bleeding? What if... I'm having a cryptic pregnancy were you still have "periods ". Like I said I know I'm not but each month there's that tiny voice in the back of my head that is over analysing everything, like right now... I'm still experiancing my PMS symptoms which normally go away once i come on... and it makes it worse how PMS and pregnancy symptoms are the same. Anyway, just needed to vent to people who would understand.