The relationship between siblings.....

I don't know where to post this so I am sorry if it's in the wrong group.

I had my daughter young, at 15. Waiting to have another child until I found "the one". Well, I finally found him and we've been married for almost 3 years. We started ttc a little early in the relationship but after we were married. We've been trying for 2 years and still nothing. I'm afraid that if I do get pregnant again (our daughter wants a sibling) that she won't get along with the baby. She's 6 years old and has a nurturing nature. Backstory we conceived in May 2018 but ended up being an ectopic. I had to have surgery and they decided to take my fallopian tube on my right side. I now only have my left. We moved states and I was able to go to the OBGYN and she rudely told me that if I had kids once then I can have them again (which I do not agree with). She also said that my husband is the problem, which we know he is not. I would like advice on both of these subjects and/or others experiences. TIA