Aww don't feel let down hun how long have you actively been ttc now? I found this info:
Normally fertile couples have a 25 percent chance of getting pregnant each cycle, and a cumulative pregnancy rate of 75 to 85 percent over the course of one year. Still, some healthy couples can take even longer to get pregnant.
You've just got to stick with it, maybe try not testing each month. I now only test when i am late so i don't get my hopes up and get disappointed everytime i see a bfn. xx