I need help boosting my fertility

I have had 3 pregnancy I have two living children. In between my two I had a miscarriage. My youngest is now 6 and I'm 26. I've never had a problem not getting pregnant but this time around. I'm getting so discouraged.weve been trying for almost a year now. We take vitamins, use the fertility lube, we eat pretty good, drink lots of water, we don't exercise persay but our work requires us to basically exercise. I'm just to the point now we're I don't want to be around our friends because they are all becoming pregnant. Any help would be appreciated 😔