It makes sense that you feel better when you tell yourself you're doing the best you can right now. Saying that reminds you that while life isn't perfect, you're staying true to your beliefs and morals and continuing to work and care for your husband and baby.
You really are under a fair amount of pressure as the main breadwinner and mother of a young baby. Remind yourself that anyone in your shoes would also be struggling and having to work hard to keep her spirits up.
Even though it may seem that others are perfect (from outward appearances) remind yourself that no one gets through life without challenges, and the best we all can do is do the best we can to meet the challenges and keep moving one foot in front of the other, day by day.