Already with a cold for 5 days, only hard coughing, there's still a chance to develop conjunctivitis? if enter in contact with my own saliva/mucus?

Yes, but less likely: The nose, throat, and eyes tend to get exposed to the same germ at around the same time. If an upper respiratory virus has infected a person, he likely would have gotten symptoms in all 3 locations (nose, throat, eyes) by the time 5 days of illness have passed. One can still get conjunctivitis later, but it's less likely. Of course, he can also catch a new germ while recovering from the first.

Yes: Viruses can be contagious for 2wks. Do you have symptoms of conjunctivitis?