Eva didn't visit her owl since she was back at Hogwarts, not because she didn't have letters to sent, but more the opposite: she did have a lot of letters to send, she just didn't find the courage within to do so.
"I have to get this over with..." she whispered to herself, looking at the two letters she held on her hand. One was the regular letter for her mother just to let her know Eva had arrived and everything was fine. The other one was an elaborate letter to her muggle bestfriend, Danny... The one that had kissed her earlier in the summer. Eva looked at the letter again and finally made up her own mind. She was not ready to talk to Danny just yet, so she called her beloved Snow and gave her the piece of parchment meant for her family.

Hi. I arrived a few days ago but things have been kind of crazy, so don't expect news from me so soon.
Hogwarts is fine as always
Be okay.
Eva

The letter was written in a cold tone and was short enough for Chloe Longwood to understand that if she didn't make an effort, she would loose her daughter forever. Looking backwards, maybe she had already lost her.
It's life.