Signed the Hiring offer of the school and there is no way out, except the end of contract!

I applied for a teaching possition in August and immediately after I was hired the Directress let me signed that what she called "contract" But I think it is not, What is being stated there is the hiring offer and the duration of service only. It does not say anything about resignation or termination of contract all it states is that" I will be working for the school with a salary of 9,000.00 Php and it will be for one full school year, that means it will end in March 2013.

Now, two weeks passed by and I just realized how cruel their system actually is. I have 10 Preparations everyday and the parents their as cruel as the administrators. I want to get out of their, I want to resign.

NOw questions:

1. I want to quit! Is it o.k. if I just file a resignation and disappear?

2. Can I use my being an inefficient teacher, so that in that way they will just let me go.

3. If I pursue on really leaving the school as early as now, will they really sue me in court? How much do I have to pay for a breach of contract?

4. I am currently enrolled on my Master's and the school frequently hold activities on a saturday which greatly affects my studies, can I use this as an excuse for them to just let me go?

Please help me solve this problem and tell me what I can do.
thanks