Anxious about baby number 2

Just found out I’m pregnant with my second baby! So excited and thrilled to give my boy a sibling and best friend. I had a tough time adjusting to motherhood with my first but now it’s the best thing ever and I love being with my son every single day and seeing the world through his sweet eyes. He is my best little buddy. So I thought I wouldn’t feel anxious and scared and especially not sad about this second pregnancy. But I feel so anxious about how it’s going to change things. And my relationship with my son. And also my relationship with my husband. I guess I thought I wouldn’t have these feelings because I thought, hey I’ve already done this before! But here I am emotional and can’t seem to feel excited about this life inside of me. I feel selfish and dumb. I wish I didn’t feel these things and I wish I could just enjoy something for once in my life instead of overthinking every good thing that happens to me. Any encouragement from you ladies would be soooo appreciated.