Last year while I was dating someone and kissed a lot, within days that person reported feeling sick (mild fever, weakness, maybe cold too, sinuses to be exact)... It was a long distance so couldn't test this aspect out... . Now I'm with someone since barely a week and again, upon kissing a lot, within days, this person is reporting mild fever, weakness... (Not sinuses tho). I have a weak immune system, most mornings I sneeze a lot and I generally have a constant headache maybe due to migraine (just extra information). . Should I get myself checked? (Of course I need to) .. .. .. But what should I even get checked for? That's my question. Do I have some kind of contagious flu kind of thing which I don't realise I have?