xanax is a benzodiazepine....so you can become addicted to it, especially it using it for a long time, or in larger doses (1mg twice daily is sorta big...usually you're started at .25 or .5mg.)
It sounds as though you're just having a few withdrawal symtoms, thank goodness they aren't more severe. I would also imagine, since the xanax makes you sorta 'la-la la' ish, it does have some impact upon your BP,...thus maybe that's a tiny part of that. And, BP changes so rapidly...and can be from anything, even after a meal, your blood pressure will be higher.
Does this 'heavy weight' on your chest, like....is it excruciating? Are you SOB, dizzy, sweaty all over? If so, you NEED to call 911 and chew a normal aspirin tablet (unless you're on blood thinners; then just call 911). i'm a nurse on the cardiac floor; women wait a long time and tend to minimize symptoms. It could possibly be anxiety, as well, since you've been off the xanax a few days, and it was an abrupt stop of a larger dose. But, only you know how bad it is. worst case scenario, it's only anxiety, but if you're still having chest pain....you need to take action. Better to be safe than sorry
I hope I've been of some help. I would call ur doc to get a refill on the xanax ASAP....and, ask him/her or their nurse to call you back TODAY and run everything by them..
good luck
High Blood Pressure and Medications?? 
