Hi I am Dr.kadhir,
Common cause of enlarged uvula
and irritated throat are viral or bacterial infection. It can also be due to allergy
(as you mentioned)
Resting the throat and taking adequate fluids (warm water) is best treatment for stress or over use. Along with this salt water goggling will be highly effective if done 4-5 times a day. Honey will give a soothing effect for the throat and uvula, you can really try it.
Bacterial infection, usually have high grade fever and can be treated with antiseptic mouthwash, which should be goggled regularly at least 5 times a day until the sore throat
or any other antihistamine along with saline nasal drops will take care if you have cold and allergies.
Antibiotics are usually not needed if it is a viral sore throat, but it is better to take a throat swab if you are starting antibiotics, when there is high index of suspicion of bacterial infection.
Thank you for the consultation in health care magic.