Is it normal for my blood pressure to spike every time I have severe anxiety/panic attack? Took 1.50 Xanax (alprazolam) and my BP was still 138 at the drs.

138 Systolic? Hoping you mean your blood pressure was 138 systolic (the top number)? Yes, your blood pressure increases with sympathetic discharge like you have during a severe anxiety or panic attack. It should come back down within a short while. The good news is that your heart is resilient and can deal with BP changes. Hoping you're working in therapy for anxiety also, and not relying on meds alone.
Yes, that will do it. During a panic attack, a state of "fight or flight" or physiological crisis, is produced: high blood pressure, muscle tension, rapid heart beat, sometimes shallow breathing with feeling of not having enough air... The goal of treatment is to stop these panic attacks. Although not deadly, they are disturbing and uncomfortable. Discuss with your md how to adjust the meds for better results.