I suspect your pregnancy may be something to do with it, but if your contract specifies that work will only be allocated as needed, I don't think there's anything you can do about it. If it's only a small hotel , they have to have reliable staff - their business depends on it - so the reality is that the hassle of coping with your maternity leave would be a major problem for them. I don't think you will be able to successfully pursue this, especially if you don't have a permanent contract, disappointing though this may be for you.