This doesn't sound right to me at all.
He's already said he'd give you 2-3 days' worth - if you're that close to giving up college (please
please try not to, by the way) he should be trying that.
Can you go to another GP? It sounds like yours doesn't know what he's talking about if he insists there's one 'best' SSRI for everyone. To me it also sounds like he doesn't know much about panic and anxiety...if you're taking someone off an SSRI (which can cause anxiety) diazepam's often used to help, and if they already have an anxiety problem...well, he should be doing more imho.
Have you tried talking to anyone in the meantime to help you through? Panic phonelines?
Really feel for you, hope you feel much better soon