Probationary is irregardless of your contract duration.
I wonder if there is any employer who will allow you to go home at anytime as you wishes depending on your reasons.
An employment involves contractual obligation which will benefit both parties (this is the presumption of the contract) as I told you, your desire to go home should be discussed to HR so that when you ask for it, there will be no haggling to have it, but to me, it may work against you!