okay I need some help ladies

Sa
I need help, this will be the 4th month my fiancé and I have been trying to get pregnant I've done everything from opks, to checking my CF to still laying there for 15 minutes after sex propped up. My period is ending in one day. It started the 17th what have you guys done to get pregnant I don't care who replies if you got pregnant the first time trying or what I need some help and I'm honestly sick of going to my doctor he's not helping at all, all hes saying is "it'll happen don't give up" we have two kids already a 6 and 3 year old with my 3 year old I was pregnant instantly but since my c section it seems like it just doesn't want to happen. I ended up pregnant last summer and it ended in a miscarriage so we stopped trying and picked up again 3 months ago.