Is this normal?

I am 6 weeks pp. The first two weeks I had the baby blues VERY bad.. I finally started to feel like myself again about 4 weeks pp. My beauty is sleeping better at night too, which has really been helpful and making me feel human getting a decent amount of sleep at night. I have been happy and enjoying my little one lately. But sometimes I get in moods where I feel anxiety and kind of down/depressed, it usually happens when I am pretty tired.. but I'm not sure if this is normal. I love my daughter so much and I don't have thoughts of harming her or myself, but sometimes I do wonder if we didn't wait long enough to have her. We got pregnant (on purpose) 3 months after getting married. I also have two step daughters, 5 and 8, who are with us one 50/50 and one every other weekend. I have wanted to be a mom my whole life, I love children so much. And it makes me so sad that I don't feel like I'm a good enough mom. She is the most perfect little thing and I just wish I didn't have these thoughts. I can't tell if my hormones are still regulating or what.. Anyone else feel this way but NOT have ppd or ppa? Anyone care to share their own experiences in relation? Am I the worst? Thank you in advance