Scared to be happy 😭

I feel like a horrible person. I had a MMC at 12w4d in May and it broke my heart into a million pieces. I'm currently 7w1d today and is it wrong that I care so much about this baby but I don't want to get attached in fear that I'll end up heart broken again? I worry all the time. I have my second ultrasound tomorrow and I'm terrified because I'm so scared something will be wrong. I talk to my mom and about what it and she tells me "she never wants to hear me say anything about something happening again" but it's the reality of the matter. I feel like such a bad person, I cried tonight. I of course love and care for this baby so, so much.. but at the same time I'm scared to be happy.