Hi there...it is always unsafe to have intercourse with unknown individuals, even if you protection. Because there is always a risk of unknown condom break or body fluids coming in contact with each other. Now it is difficult to tell if the present symptoms are related to sexually transmitted disease. They could be completey unrelated. Did you have any genital erosion or ulcer or burning micturition in 1 or 2 months after intercourse? Now all you can do is get evaluated for cold and sore throat by a ENT specialist. Along with it you can get tested for most common chronic sexually transmitted diseases like hiv, syphilis and hepatitis b.