malu, you need to talk to your advisor's boss. If there are other people doing research in the same area, you may be able to switch to one of them. You also need to talk to the university's personnel office. You are an employee and you have rights.
If you are acquainted with another professor whom you like, approach them directly and see if they need another research assistant. In that process, tell them in detail what you have been working on for your current advisor. Or talk to other graduate students and find out what else may be available.
The thing you have to sell about yourself is the knowledge you have gained from the advisor.
Try this approach before you think about going home. You don't have to start over.
Good luck
Artemis
