Just check your bodytemperature. Fever = no workout
Lower intensity a bit. Increase carbs and protein a bit and take your post workout drink as soon as you stop lifting. Not 2 hour after, more like 2 minutes after. Drink water like crazy. If you have glutamine, take 10g before workout and 10-20g after. Also increase c-vitamine to 2-3g per day. Echinea is also good. Omega3 probably will help too. Sleep 8-10 hour, or more..