You can be fired for calling in sick to a job too much.
However if you really are sick and you need to call in sick then you should not get fired.
An employer is free to fire someone for calling in sick if they call in sick too often unless you have an individual or union contract in place that says otherwise.
So you should only call in sick to the job if you really are sick and cannot go to work.
If you have the flu, a bad cold virus or are contagious with some illness then you should call in sick.
However if you just have a slight headache or just a little muscle aches and are not too weak to work then you should show up to work.
Only use the sick days if you really are sick.
Jobs are hard to come by these days so you should do your best to keep your job.