My vocal range reaches an E6 but today and yesterday I can't even hit a G5, which is usually a piece of cake. Help! I'm crying!?

You might not be fully healed yet and it might also be the illness - you say you've been really sick. Look, I'm a soprano with an F6 and I've been sick enough to barely be able to hit a D5 before. It happens - and you must have been very sick for it to have lasted 2 weeks! I've also been at the stage of recovering from an illness, thought my voice was ok and had it die after 5 minutes (it was very interseting when that happened mid performance. Thank God I was only in the choir but it was horrible. At the start of the performance my sop As were a bit shaky. By the end of the performance I was miming everything above an E5 - I was losing a note every few minutes. Unsurprisingly I then took a week off to rest my voice fully! The point is - just a bug.) As the other posters have suggested - rest for a couple days, see how you are - and if you're not all better, book an appointment with your ENT to make sure your voice is ok! Better safe than sorry so if you are worried then even if you're better in a few days a check up with your ent is a good idea.

Good luck!

Indeed, you might NOT be fully healed yet. Unfortunately your audition might come way too soon, so you should have discussed it well beforehand with your vocal teacher AND with your ENT doctor! No-one here can take a look at your throat anyway, so all you can get is very uneducated guesses for a diagnosis. Go see a doctor.

I think you are not fully healed yet. Go on a complete vocal rest for around 48 hours and then see if you're better.