I want to call into work
Why do you want to call into work?
I get severe headaches and nausea from my disease.
If you are feeling sick you should call out if you truly are sick. It would be wrong to lie about a sick day if you didn't need it.
I actually just don't want to go to work today.
It sounds like you just want to get out of work. If you hate it there so much, you should find another job.