Hi Jay-Bee
You've come to the right place for support. So far its been quite a good experience for me.
The fact that you are using OPK's, but more importantly that you chart your temperature, is a big step in the right direction. If your chart shows a clear thermal shift every cycle, then you are ovulating. I've been doing it myself for the last 7 months and its amazing what you can see from it. The rise in temperature is due to a rise in progesterone after the egg is released, and should stay more or less consistent during the 2nd phase of your cycle (after ovulation). Shortly before AF arrives you will notice a drop in temperature. If your temp goes up and down a lot after ovulation, then perhaps your progesterone is on the low side. Keep an eye on a couple of cycles to see if your temperatures are stable.
It takes the average couple 6 - 12 months to fall pregnant, so don't stress. Age is a bit of a factor, so having your fertility checked at the 6 month mark may be a good idea. If you don't have success in the first 3 months after a checkup at your gynae, then perhaps go to a fertility specialist instead - I found that mine had a much better approach than my gynae.
In my opinion you should have your DH checked out too, since there is no use in doing all this if there may be a problem on his side.
I know its hard when everyone around you seems to be falling pregnant - believe me, I had my fair share this past 18 months. I wish I could say its easy to not let it get to you, but its hard work. You need to remind yourself that success may be around the corner and that there is no need to rush even though it feels like it. Getting anxious will just make it worse. And try to be happy for others who fall pregnant and have a good attitude about it - it will do your own emotions good. Hope to hear some good news from you soon.