How do I train my chi mix from being skid-dish?

I've had a "taco terrier" since she was 6 weeks. She's 7 months and is so skiddish. She's been that way since I got her. She still isn't fully house trained. She goes in the house at least 2 times a day. She has never been abused by my fam (hubby, 2 boys). We have punished her for going in the house. Nothing severe at ALL. She just won't come to any of us and if she does she'll start peeing like she's scared. I don't want to get rid of her but it's starting to be a pain. Please help.