Any dog trainers out there?

I'm in desperate need of help. 
I have a chihuahua mix that is 2 years old that I've had since she was 8 weeks. The lady I got her from was a foster and she "pad trained" her. Well, that completely f*%#ed her up because she absolutely refuses to go outside when I hook her to her long leash (we don't have a fenced backyard) and I'm too pregnant to walk her constantly anymore (I also get really bad heart palpitations when I exercise now). She has a crate we put her in when we leave and it's only big enough for her to stand up and turn around. Everywhere on the internet says "have a crate that small and they won't use the bathroom on themselves". Okay well she don't give a flying f*^% about that she will happily poop and pee all over herself and then lay in it. I try to take her potty outside every time before I leave, but she won't she will stand out there and shake even if she's out there for an hour. I don't have time to wait all god damn day so I have no choice but to let her back inside before I leave. To my surprise, I always come home to poop and pee covered in her crate and all over her. She has had 6 baths this month. I scold her and put her outside or on her pee pad inside and tell her firmly that this is where she needs to go. She don't care, she will just grab a toy and wag her tail. Getting rid of her is not an option because she is my everything but with a newborn coming this needs to stop and she needs to start using the bathroom outside like her sister does (I also have a one year old Australian shepherd). They get walks and exercise when my boyfriend gets home from work and I also take them to the dog park but it's been closed for maintenance for forever now so yes they do get out and get exercise even if I have to take them to someone's house to let them run in their backyard. If I leave her out of her crate she will get into things and chew stuff up even if there are bones and toys everywhere but the plus side is she will use her pad. Unfortunately that's not an option to leave her out though. I just need help or tips because I have 0 patience anymore whatsoever.