Trying to get pregnant recommendations?

My fiancé and I have been trying to get pregnant for about 4 months now. With no luck. I’ve been taking prenatal vitamins everyday. And also trying PreSeed. My periods are kinda different than a lot of peoples. My last one lasted 4 days and the one before that (in the same month) lasted 3 days. It’s hard to tell when I’m ovulating because when it’s getting close to my ovulation days my period hits. Any advice on what to do ? I have terrible baby fever and I really want to have one.