I am wondering if what I have is anxiety. It happens on occassion. My blood pressure goes sky high (from a normal level), I get a nervous feeling in my stomach, my pulse escalates and I get scared thinking something is terribly wrong. I take a half of Xanax, fall asleep, and wake up feeling better with blood pressure at a normal level. I have had this happen for a 24 hour period and then disappears. Is this an anxiety attack? (I have many stressors in my life so I am not new to stress.) What do you think?

It certainly sounds like it to me.
There's all kinds of ways to deal with anxiety.
Speak to your doctor about it. It you're not particularly into taking more medication, try self-help books to learn to relax.
Exercise helps---yoga, in particular.
Breathing.....thinking positive....a good diet, minus unneccessary sugars.....
You need to lessen your stress levels, if possible.
Good luck.

That's a LONG time for an anxiety attack. I have suffered for 30 years now, and control my attacks, which can often be full-blown panic episodes (HELP! I'm having a heart attack, I can't breathe, I'm dying...) with a much-reduced dose of alprazolam (3mg/day now) but the actual panics need something really fast-acting and heavily sedating like bromazepam. Then the episodes seem to dissipate in around 10 mins max. Without my emergency care pills they can last half an hour or more, which is a LONG time to think you're breathing your last... the absolute worst thing about panic syndrome is that feeling that you are actually just on the verge of death. It IS a phobia, which all people who suffer such things have; thanatophobia. For years I thought the word was NECROPHOBIA for a fear of dying, but it turns out that means a fear of dead bodies! Thanatophobia is the right word. Clearly the wrong position to be in though, and the scariest thing I ever had or can imagine having. 24 hours sounds like a very pronounced attack of generalised anxiety Disorder. Have you ever identified a trigger to it? I haven't ever found a trigger that sets me off in 30 years, so probably never will. No trigger means less chance of finding out what actually causes you to have these horrible things. There is nothing worse. Yet my panics sometimes come on at times when I am feeling no anxiety whatsoever, sometimes quite the opposite, I'm feeling good. Confusing or what? But always VERY scary.