I had adenovirus ekc in august. since then i've had strep, sinusitis and now have uri.did the ekc kill my immune system? or is it still the virus?

Maybe coincidence?: It's unlikely that the conjunctivitis (or the virus that caused it) damaged your immune system. It may be bad luck that you've been exposed to a number of infections recently. Allergies (ragweed is high now) can also predispose to infections if you're symptomatic. If you're still worried, see an immunologist. They can evaluate your immune system to see if it is or isn't functioning properly.

Secondary infection : Secondary infection may occur o Che there is inflammation of tissues caused by the viral infection. This is one possible cause. If you continue to have recurring infections, a work up is indicated to determine the cause, including immune testing.