Scared about baby #2

Don't get me wrong, I am so excited to be a mommy of two! I'm currently 17 weeks 3 days and the further along I get the more scared I get! I have a 4 year old daughter who is my world! It has been just her and I for the past 4 years up until 7 months ago when I met my boyfriend! My daughter and I are extremely close as I am the only parent she has had in her life! She is so excited to be a big sister!! But I'm scared she will end up pulling away from me, or think that she wasn't enough for me when baby gets here! We both have so many changes happening so fast! I got pregnant after dating my boyfriend only three months. He is the love of my life and I have no doubt that we will work out. He has an son who is 10. So my daughter and I will be going from just the two of us to now 5 of us! She loves both of them, I just can't help but worry! I'm getting really stressed and depressed about it! Has anyone else felt like this??