I Am 39 Years Old And Have Been Suffering From

I am 39 years old and have been suffering from panic attacks and extreme anxiety the last 4 weeks. This has caused be to become unusually inactive as it is hard to leave the house without experiencing panic. I have been on Xanax for 8 years and just recently started taking Celexa. My resting pulse is consistently in the low to high 50's yet my activity level as greatly decreased. Otherwise I have worked out regularly most my adult life. Is the lower pulse cause for concern?