Hello, There is a tremendous difference between your ability to get pregnant in your early versus your late 30s. As the decade progresses, a woman s fertility goes into free fall. That s why fertility experts caution women in their 30s not to wait too long, particularly if they want more than one child.  If you re 35 or over, you should see a specialist if you have had frequent unprotected sex for six months and are still not pregnant. Although natural fertilisation is possible with one intact Fallopian tube,your chances definitely go down if your one Fallopian tube is blocked. My advise to you is that if you have taken enough chances for more than 6 months by resorting to unprotected sex and specifically during and around your ovulation time,it is high time you meet a fertility specialist. Thanks