Super sick 10 month old

Des321

The last couple nights my son has been coughing pretty bad in his sleep, and developed a runny nose and low grade fever last. His temp seems to fluctuate or maybe my thermometer isn't accurate, but his skin feels super hot except his feet and legs. This morning he woke up to eat but was so congested he had a hard time breathing through his nose. He also looked like he was freezing because he was shivering, his skin was blotchy looking and wasn't as hot as last night. The nurse last night told me he's fine unless his fever doesn't go away or gets worse today, but why does he shiver so badly and have such different temperatures all the time? Seems very odd to me but I'm a FTM so this is all new to me. Any help from experienced parents would be much appreciated!