Feeling defeated...

I am a SAHM with two beautiful girls my oldest is 3 years old and my baby is 20 months old. I am so blessed and thankful for them! But sometimes I feel like I’m not good enough for them I try everyday to be the best mom I can but when I lay down and think about the day I am not happy. I feel defeated sometimes. Me & my husband been trying for baby #3 for a year and I haven’t got my positive so I beat myself up for that! I can feel myself going Into depression but I fight it everyday to stay strong and keep my head up for my girls I never want them to see me sad! I try talking to my husband about how I feel but he doesn’t get it. I remember one time I tried opening up to him and he pretty much said I’m not a normal mom. And I went off on him!! Anyways.. just wanted to vent and write maybe it’ll make me feel better! Am I alone?!