how can I do it?

I've been on citalopram for 2 years now and it's not working at all, I just started university and my anxiety is awful, I am having panic attacks constantly, I saw him today and asked for it but he was reluctant to give me it, I don't want to have to drop out because of this but I can't carry on in this condition, shouldn't he HAVE to give me it if it's going to help me? he said if he did give me it, it would only be temporary like 1-2 days worth..