With baby #1, I got prego without trying. Then baby #2, after SIX MONTHS I was still not pregnant. My baby was over three years old, and I'd had my cycle back for a while. I could not figure out what the deal was. I was even doing my temps and tracking when I was ovulating, etc. I could not manage to get pregnant, though.
In the end, a friend (herbalist) suggest I start drinking Red Raspberry Leaf Tea (it's herbal and great for all girlie things! It actually gets rid of PMS for me as well and lightens my period and takes away cramps as good as meds do). Anyway, so I was heart broken I wasn't pregnant yet. My husband was done trying, and this was my last chance.
After my period, I started drinking Red Raspberry Leaf Tea three times a day, every day. That's the time I ended up pregnant. If you're having any hormonal issues, RRL tea helps to balance hormones and increase fertility. So, if you're not pregnant, I HIGHLY recommend using this stuff. From seeing what this stuff does with my periods and then with fertility and even helping during pregnancy, I'm a huge believer in it now.
I don't know why sometimes it's harder to get pregnant than other times. I've since had three more pregnancies since then (we're prego with baby #5), and #3 & #4 were super easy to get prego. Then #5, we weren't even trying and got prego. So, it doesn't necessarily mean it'll be more difficult in the future should you want to try for more!
I feel the same as you - I HATE WAITING TO TAKE THE TEST!! And, I also feel bad feeling stressed over it when there are those that take YEARS to get pregnant. It doesn't lessen their grief or stress by you being stressed that it's taking you so long for YOU. You can't help how you feel...and my heart goes out to women who really, really struggle with getting pregnant.
I hope you're prego!!
EDIT: I just read the other comments. Relaxing is a good idea...but not always as easy as it is to say! You can be a stressed nut and still get prego. It's a rare case for stress to prevent a pregnancy. If you're like me, you'll start stressing over the fact you're feeling stressed and then feel more stressed! So, feel stressed if you feel it (allow yourself to without getting upset over it), try to calm yourself if you can, but if not, odds are it has nothing to do with your problem in getting prego. Are you nursing at all? Maybe your cycle isn't totally normal yet. Or maybe it'll just take a bit more time. It's normal for it to take a little while sometimes.