Agreed that more info is needed here. And Keif' makes an important point about the potency differences.
But OP, another important thing to note is that Clonazepam is pretty significantly longer acting than Alprazolam. By about roughly 3x the half-life.
Alprazolam is super popular, and was one of the most prescribed meds in the US for a while, if I'm not mistaken. But in my opinion, and in the opinion of many medical professionals I've spoken to, alprazolam is more appropriate for infrequent, but intense panic attacks. It hits quick, it hits hard, it should stop most anxiety attacks in their tracks, and then the effect goes away relatively quickly, at least compared to other benzodiazepines.
Clonazepam is more appropriate for regular & consistent usage, although most doctors will advise against LONG TERM regular usage. My doctor, for example, prefers to start anxiety patients on clonazepam, while also trying different SSRI's for long term therapy. Once an effective SSRI is established, the benzo is removed, or tapered off if physical dependence is a concern. Regardless, it's much longer lasting. It's quite common to take clonazepam before bed, and still feel some effects around lunch time of the next day. Of course, tolerance comes into play like any other controlled substance.
I say all of that to give you an idea of what may be appropriate based on the type of anxiety issues you have. But ultimately, you need to speak with your doctor. If the Alprazolam is having undesirable side effects, a reasonable doctor should be willing to work with you. If he's really against clonazepam (which I find odd, since alprazolam is generally considered to be one of the more "dangerous" and abuse prone benzos), there are other benzo options available, such as diazepam, lorazepam, etc..
Again, ultimately, this will be between you and your doctor. I would stop taking the Alprazolam now if the side effects are that intense, and give your doctor's office a call today. Good luck!