Running with cold

So, 4 weeks until Paris marathon, supposed to be running 22 mies today however I have a terrible cold. Sore sinuses, blocked nose, headache, little bit dizzy and lethargic after a night of very little sleep. Should I 1- stay at home and not run 2- do a short, slow run 3- just go for it! I always get a cold around 7-10 days prior to a marathon but never had one at the peak of my training. The longest I've managed to run so far is 18 miles, missed a run last week and cycled 27 miles instead. Had a but if a cough/sore chest earlier this week but still managed a 4 & 8 mile run but then got hit with this yesterday. Not sure if my runs brought it on or if it was coming on anyway. Any advice would be gratefully received x

don't run - you need to rest and recover. don't run again till you are properly better - might be a day or two after you feel ok

Thanks mathschick but what about the rule that if it's neck and above then you're ok to run but if it's below the neck i.e. chesty cough, then stay at home? I'm concerned that I end up doing a long run to close to the marathon and scupper my chances of a PB. The marathon is 5 weeks tomorrow.

if you feel bad then you won't benefit from the training anyway and will just make you worse. I think that rule is a load of cobblers to be honest! if you have a headache and feel dizzy then you can't train properly anyway! you'll just end up being ill longer and missing more runs. If you regularly use a heart rate monitor and know what your resting heart rate is then, then you can guide whether to run or not based on that. if your resting rate is 10 or more above normal, don't train

The above neck/below neck thing is just a guide.  If you have a headache, are feeling dizzy, and are very tired, then you're not well enough to train.  Rest.