Throat problems

Since the start of this year I have had a continuous cold and no amount of medicine has made it better. In fact it's gotten even worse lately, I finished antibiotics a few weeks ago but it hardly even helped. Now I can't stop sneezing and my throat is killing, so I took a look at my mouth and the roof of my mouth has like blood spots and the back of my throat looks disgusting and it is covered in white spots. Does anyone know what this is and how could I get rid of this?