Am I contagious??? Help!?

I woke up Tuesday morning with a soar throat, congested head and slight fever (99). The fever was gone by Tuesday afternoon and has not come back. My throat feels ok during the day but it is soar when I first wake up. The past two days I have been coughing up yellowish-greenish phlegm. I don't feel too bad other than the coughing. I'm not sure what I have. But does anyone know if I am contagious? I'm supposed to host Easter lunch tomorrow but I don't want to get everyone sick!