yikes, your phone doesn't last from 8 to 5? also are you taking notes on your phone? how are you using it when you are in school? i must be really lucky, i got a replacement 4S for dropped calls (and i'm pretty sure its my service provider, not the phone thats the problem anyway) and both the original and replacement lasted ~2 days with moderate usage.
anyway, on topic, when i was trying to get my service provider to troubleshoot my dropped calls, they told me to use the phone without 3g for a week and see if it helped. when i said i didn't have a 3g toggle in the phone settings, they effectively said there was nothing they could do. it was kind of a garbage response, but seeing as how i still get dropped calls on my replacement unit in the middle of downtown toronto, i'll at least be able to play their little game once i have a 3g switch.