I've been having swollen tonsils for about 2 weeks, what could it be?

Several things. Could be an infection (typically will have associated pain); cryptic tonsils where they get large, trap debris, and then stay large. If only one is large and not the other, or if they do not go back down to your "normal"size, you should see your doctor to rule out a problem that may require treatment (bacterial infection, tumor).
Swollen tonsils. It could be an infection. Try to gargle with warm water with one quarter teaspoon of salt in 8 oz of water. Three times per day. If swellin persists see your doctor.