Rescheduling g2 test

Am I able to reschedule my g2 test? Online it says I can, but my driving instructor says he can’t push it back because it’s booked for tomorrow morning and it’s within 48 hours notice. The thing is I got REALLY sick 2 days ago and I really don’t see the point in taking the test if I feel like this. Yesterday I had my last lesson with my instructor and I tried to push through it, but it was the WORST lesson i’ve had so far. I had taken so much medicine that I was just drowsy and making stupid mistakes that I’ve never made before (like missing a stop sign???).

Also, because i’ve been sick I haven’t been able to practice the route this weekend like I had planned and I just don’t feel prepared at all. I wish my instructor would’ve told me earlier that I can’t reschedule if I get sick because he’s known for almost 5 days now that I wasn’t feeling the best.