TTC for 7 months...advice..encouragement needed?

My fiance and I have been TTC for 7 months. Well, this is the 7th month and I will find out in about a week and a half if we succeeded this time. I take prenatal vitamins but that is about as far as it goes. I hear stress can make it take longer so we have every day/every other day throughout the month. I am getting discouraged. I know many people take years to get pregnant but I am worried. My fiance already has 2 kids from a previous marriage and I got pregnant once. I was on BC and it was not planned but I had a miscarriage. Does the fact that I have been pregnant before and he has kids help our odds of getting pregnant? How long did it take you to conceive? I am nervous that I can't have kids. I think anyone would feel this way but until I become pregnant, I think I'll have doubts. My periods are very regular and I know I ovulate. I don't have cysts or anything in my ovaries so I don't have PCOS or anything. Advice, encouragement, help would be great. Thanks.