A healthy couple can take anywhere from 6 months to a year to conceive a child, sometimes longer. It's all to do with timing, and everything happening at precise moments. The sperm need to be in the correct place at the same time as the egg, and timing for this can be tricky if you're unsure of your ovulation cycle. And even if the egg is fertilized, it might not implant.
Stressing about it will only cause problems. I know it's hard, but try to relax. Sometimes letting nature take its course is more effective. Try to focus on an intimate, loving relationship with your fiance and just try to make love as often as possible. I wouldn't bother with pregnancy tests unless your period is late, as your mind can play tricks on you when you start the "am .I?" game.
I'm sure everything is fine, honey. You're probably fertile as can be! Remember to just have fun with lovemaking, keep it intimate instead of making it a job (which is something conceiving couples have trouble with) and leave the rest up to your body. It knows what to do. My hopes are with you. :)