With enough love, care and structure, all children can become happier beings. Babies are very difficult to understand, and need to be approached with a great deal of care. Sometimes, children that are deemed horrendous by their parents simply need some schedule tweaking and rule implementation.
I find that they do best with adhering to a very strict schedule that keeps them becoming too tired or under-stimulated. Nap and sleep time should be the same each day, as should the schedule of events like getting dressed, meals, play and baths. Keep a log of her behavior for a few days so you can note what seems to upset her. You should be able to get a clearer picture of what she likes and doesn't like, and how she responds to certain situations.
Since you're home all day with her, I'd break up her day into very small
segments that could be repeated each day. Children love routine and knowing exactly what is going to happen next. For older babies, I like to break activity sessions into 45-60 minute blocks of structured and unstructured play. A baby simply can not stay in the same room doing the same thing for several hours without getting bored and acting out.