Termination During Probation
The company can terminate you without reason during probation. They do not need to confirm you; it's a choice lying entirely with them. In general, companies frown on leaves during probation and definitely don't like unscheduled and unapproved leave. It is natural that the company will, therefore, be unhappy.
Employee Behavior During Probation
It is generally considered that if an employee does not behave properly during probation, it's unlikely they will be a good employee during confirmed/permanent status. Sending out just an SMS during an absence, without even calling and informing the manager of your problem, is generally considered unacceptable.
Steps to Take if Facing Termination
If they decide to terminate, there is very little you can do. I suggest you go and apologize to your manager and explain the situation.