I'm new!

Hi all,I'm new to this and just looking for support from others. I'm 34 with 2 lovely children but TTC #3. Every time my period starts I feel angry and depressed, like all my efforts were in vain 😢 I conceived my 2 children so quickly and presumed i would again. Am I being selfish? Don't have anyone to talk to at all,even my partner doesn't understand my frustration. He's of the opinion "just keep trying " I would consider myself healthy, I don't smoke or drink alcohol. I'm from UK 😊