The domestic violence hotline is great advice. I would definitely look into it. The text messages are harassment and you should be able to do something about it.
If you're worried about your child while she's in your ex's care you can also contact child protective services. They will at least do an assessment. Depending on your child's age they may talk to her as well.
For your own soul I would recommend finding an al-anon meeting. Sharing keeps me sane and I feel better pretty much immediately. Keep coming back.