Tonsils are red as well as back of throat, palate is yellow with red dots. heavily congested with large amount of yellow/palemucus. what could i have?

Tonsillitis: Could be tonsillitis or tonsillopharyngitis. Could be sinusitis if the yellow mucous is coming from your nose or sinuses. If symptoms have been going on for more than a week, you should seek care and possible cultures. You might need antibiotics, but an evaluation of your nose and throat would be necessary to make that determination.

Get treatment: It can be many different causes i suggest you see an ENT doctor.