Trying to conceive

Me and my partner been trying almost for 6 months already and nothing comes as positive both we are on healthy conditions been tracking my fertility days and everything when to the doctor and everything looks perfect we have two kids already 7 and 5 years old but we really want to have another one I have a lost las year on May on 14 weeks no found baby heartbeat :( can some one help me or try something else it is first time using this app :) thanks