Help 😔

My fiancé & I have been trying for awhile now to get pregnant. My period is irregular. I only get it twice to four times a year. I have had one or two times that i thought i was but ended up with negative results. I tried geritol pills because someone recommended them to me. The worst feeling is being a girl & not being able to give your own fiancé a family. I don't know what to do anymore. I just wanna give up. I'm stressed out and my fiancé keeps pushing me for a baby. He doesn't get how stressed out i am because i feel like I'm failing him and it's just breaking my heart .