Personaly, I think your son is a bit young for teething. Most babies don't cut teeth until they are closer to 8 months. If a baby has cold like symptoms, it's a cold, not teething, the "cold-like" symptoms and teething association are a myth and it's bad advise to assume otherwise. A fever of any sort should be followed up on with your doctor. Most babies around 5 months start drooling excessively due to the over production of saliva. A baby has no control over anything, EVERYTHING is unbalanced in a child this young and the body is constantly growing, hormone levels are changing, and learning is occurring. Salivary glands are a good example of this. The age your son is now is when he starts having awareness of his surroundings and memory develops. Children this age start having what is called night terrors. It's when they are in REM sleep (dreaming) and in their dream they have dropped something or they are hungry or you leave the room. Things that they normally fuss about in their wake hours.
Both of my kids have gone through this. I, like most people, took advise of others a knuckled it down to teething and of course, medicated my child when he didn't need it. (In which I absolutely despise) Finally I did my own research and all of the things occurring with both of my children (my youngest just went through it) fit the critera of night terrors.
Handeling it is one of 2 ways. Let them cry it out or soothe them through it. I soothed my kids, I don't believe in the crying it out. I hope this helps, good luck.