Anyone else happy but terrified?

I’m SO excited for this baby!! But i’m also so so scared. I have one daughter right now, she’s almost 4. I got pregnant with her when i was 16 years old and gave birth to her when i was 17. Her father and i stayed together and are now married but it was probably the most traumatic 9 months of my life when i was pregnant with her & neither of us had any what we were doing. And now 4 amazing years later, we are expecting are second one, we didn’t plan for it but it happened and I’m so happy & so excited but i’m also so scared. i’m only 6 weeks but can’t stop worrying. I only have sad memories with my last pregnancy and i’m so worried on how the adjustment from 1 kid to 2 kids will go. I worry i’m not gonna be a good enough parent. Please send all the good advice & messages, i need it!!