Ten years ago I drove a 20', 6-wheel box van for a small co. in Il. It was 90 miles south of Chicago on US24. I had to pick up air freight at O'Hare and at import warehouses all over the city.
I got sick and tried to tough it out. Wrong move. One day at home base I could barely get up in the box to unload. I didn't ask them; I TOLD them I'm going to take the rest of the day off to see a doctor.
Good move on my part as I definately had pneumonia. When I got home I called in and told them the news. The only thing they asked was "Are you going to pick up that load tomorrow?"
Yeah, I'll get right on it. Know what? That load was still there when I got well enough to drive.

 

If the carrier is telling you that the load must go on, no matter if you're sick or not, point them towards this little DOT regulation:

§392.3 Ill or fatigued operator.


No driver shall operate a motor vehicle, and a commercial motor carrier shall not require or permit a driver to operate a commercial motor vehicle, while the driver's ability or alertness is so impaired, or so likely to become impaired, through fatigue, illness, or any other cause, as to make it unsafe for him/her to begin or continue to operate the commercial motor vehicle. However, in a case of grave emergency where the hazard to occupants of the commercial motor vehicle or other users of the highway would be increased by compliance with this section, the driver may continue to operate the commercial motor vehicle to the nearest place at which that hazard is removed.

[35 FR 7800, May 21, 1970, as amended at 60 FR 38746, July 28, 1995].

http://www.fmcsa.dot.gov/rules-regul...ction_toc=1803

The interpretation:

§392.3 Ill or Fatigued Operator


Question 1: What protection is afforded a driver for refusing to violate the FMCSRs?

Guidance: Section 405 of the STAA—Surface Transportation Assistance Act of 1982 (49 U.S.C. 31105) states, in part, that no person shall discharge, discipline, or in any manner discriminate against an employee with respect to the employee's compensation, terms, conditions, or privileges of employment for refusing to operate a vehicle when such operation constitutes a violation of any Federal rule, regulation, standard, or order applicable to CMV safety. In such a case, a driver may submit a signed complaint to the Occupational Safety and Health Administration.

 

If you are sick you don't need to be out on the road driving. If you are away from home park it in a truck stops somewhere. If a company insists you drive while ill, you need to let them have their truck back. You don't want to be involved in an accident because you drove when you were ill.

 

I spent almost 3 years OTR and was sick once. And it was a lame outer ear infection. It was difficult to sleep, but I managed to not crash. I made it from Salem, OR to Tremonton, UT and finally found a place to park where I could see a doctor. They gave me the antibiotic ear drops and I was finally better when I got to Indiana.