Childcare worries

I'm nervous as hell. My daughter can be a really happy /cheerful girl who is constantly smiling and wanting to play with everyone. On the other hand my daughter has about 5 tantrums a day, when she's frustrated she'll throw herself back and make a big fuss if she can't get hold of something she can't have. She doesn't really sleep well any time of the day, she doesn't want to eat ANYTHING at the moment. Refuses any other milk besides breast milk, she was literally cry for ages but I'm going to have to be more serious about weening her. I'm not going beyond a year with it. Also she's had bowel issues and sometimes has nappy explosions. We went to visit a childminder the other day and it was really messy. I am really worried about leaving her. I know she'll gradually get used to her surroundings, I just know she isn't an easy child. 😢 😢