Common Cold: Too Sick to Work?
If you've had a cold for a few days and are now coughing up darker yellow mucus, it's still probably just a cold. If you continue to cough up dark mucus after a week, it's a good idea to see your doctor. If the cough feels deep and makes you feel short of breath, it's probably more than a common cold. These may be signs of something more serious such as bronchitis or pneumonia, so call your doctor immediately. Stay home from work.
For more information, see WebMD's When a Cold Becomes Bronchitis.
If your ear really hurts and you can't hear well, you could have an ear infection. Congestion from a common cold can also cause ear pain. In either case, you need to call your doctor to find the cause. You may need an antibiotic or pain-relieving medication for the earache.
Ear infections are not contagious. However, if you have cold symptoms along with an earache, you are likely contagious for the first two to three days.
For in-depth information, see WebMD's Earache: Cold or Ear Infection?
If you have pain around the eyes, top of the forehead, the cheekbones, and even the top of your teeth, it may be a symptom of a sinus infection. Go ahead and call in sick. The next day, you'll probably be able to go to work as sinus infections aren't typically contagious. If you are very sick or if your symptoms get worse after a week, then call your doctor. Antibiotics do not heal people faster for the common “acute sinusitis,” but occasionally a bacterial infection can set in later which requires an antibiotic.
For more information, see WebMD's When a Cold Becomes a Sinus Infection.
If you wake up with a headache, it may be a cold, especially if you have other symptoms such as sneezing, nasal congestion, and body aches. In that case, you may need to stay home a day or two while you're most contagious and feel the worst.
But if you have a headache and can't tolerate noise or light, you may have a migraine and shouldn't be at work. If you have recurring headaches and haven't seen a doctor, make an appointment. A doctor can assess the cause of your headache. There's no point in suffering with them. There are drugs you can take for migraines and other chronic headaches that start working within the hour and shorten the migraine's duration.