I left my daushand in dog daycare for five days he now have not been very active he is fatigue ,has lack of appetite and sniffles like he is congested sometimes lick his paw

Doggy daycare where you picked him up at the end of every day? Or boarding?
Not that it really matters, just wondering if you saw him each evening at the end of those five days.
A change like this deserves a trip to the vet. It would be in his best interest to get a handle on it quickly rather than taking the chance that it gets worse.